Leelan, you are certain your hunch is correct.  These glyphs carved or somehow woven into the stone of the door are the trigger for magical traps.  Opening the door would almost certainly trigger them, to unknown effect.

It might be possible to deface or alter the runes in such as way as to disable them, but it would be very dangerous.  One wrong move would almost certainly trigger the trap.

[Does Zap have arms with which to open a sliding door?  I suppose it would be possible for Zap to open them, but Zip is so small I don't think it has the umph to slide open a stone door.  Does Zip have a carrying capacity or any notes about what it can lift?

If you go the route of trying to disable the traps by defacing or altering the runes on the doors, it will be an arcana check.  I need to know which door you are doing first (north or south) and who is in the room, if anyone, along with the person attempting to disarm it.  A failure will have consequences.]

Rohuzar will remain in the room, and assist Leelan if asked. He'll watch his back if not

((apologies for the delay in replying. Zip has no rules on carrying capacity, but it's a tiny creature with 4 strength, so using the carrying/lifting rules would result in a very small number. Zap also has no rules, but it's a medium creature with 14 strength, so using those general rules, it can left/carry just as much as Grugga can. However, it has no arms... it's just a giant spinning top with crystals on the edges. If there is a way to get them inside, they're both immune to poison damage and the poisoned effect.))

Grugga offers his constructs gladly  for searching the tomb, but he expresses doubt that they will be able to open the door, unless there's some sort of pulley system that Zap could wrap around itself to open the door.

Leelan will attempt to deface the sigil on the northern door. He’ll try to focus as much as possible on the task at hand, knowing that failure could spell disaster. He’ll ask Rohuzar for help in case he needs an extra pair of hands for this attempt.

Arcana (with advantage from the help action from Rohuzar assuming I’m allowed to): 18

11

[No one said they left the room, so I assume everyone is hanging around to watch Leelan work and help collect the remains afterward...]

As the party looks on, Leelan carefully approaches the northern door.  He takes mental note of the areas most likely to accept alteration without triggering the glyph... a bit like carefully extracting only the Queens from a house of cards without crashing down the whole structure.  

A bead of sweat running down his brow, the gnome painstakingly scrapes at the surface of the stone, chipping away layer by layer at each critical point.  The effects of his detect magic only increases his anxiety, for each time he makes contact with the door, he can see the glyph pulse with power, in expectation of release.  He realizes he has been holding his breath through the process.

With a last bit of chiseling he removes what should be the last important piece.  In doing so, a small chuck of stone breaks loose from the door and falls at his feet, making a loud 'clack'.  Leelan can see the glyph light up, bright as the sun.  The others can only see Leelan raise his hands over his eyes and step back.  As everyone begins to react... Leelan sees the light fade and drift away, like flecks of dust blown by a light breeze.  He has successfully disabled the magical trap on the north door and it slides open easily without incident.

As the door opens, the 10 minute duration of his spell also expires, and the detect magic has worn off.

Beyond the north doorway is stone chamber 15' wide by 35' long.  This is the chamber that when Grugga heard it described by Aubrey, it sounded to him like a museum.  There are multiple items here, displayed on marble pedestals or hung from the walls.  There are hammers and chisels, heavy saws, borers, and a collection of plumb bobs, one hung from the center of the ceiling on razor thin piece of wire.  There is a water level on display, next to a corner square and a compass.  Some of the tools are gilded and look ceremonial, while others are made of wood or common metals and show the wear of ancient use.  In addition to the tools, there are geological samples on display, several large crystals and an open geode, nearly a foot across.  Finally there are four statues in the room.  They depict laborers, two working together to wield a giant saw, one kneeling with a hammer and chisel, and a fourth standing and holding an object to his eye, something like a small, boxy looking glass.  There are no doors leading out of the room.

     "Who built this?" Raqisat asks rhetorically.  "Where they so removed from actually building things that they had to make a museum to remember how it was done?"

     Raqisat has only looked from the original room though, not yet moving into the new one.  His eye was scanning the room closely though, noting the smaller pieces he could possibly take and conceal unnoticed but also thinking it was too soon to be taking risks.

Aubrey ponders Raqisat's question, hoping to be able to provide him with more than a guess.
History: 16 Another roll if Aubrey would have advantage: 7

He then stays by the door, scanning the room for threats.
Perception: 7

(How life-like are the statues?)

Rohuzar would like to examine this stuff for what's valuable and what is not

Once the trap is disabled, Grugga can't help but move in and take a look. He whistles a note of approval upon seeing the construction tools. "It's a shrine to the Cornerstone. Whoever's in that sarcophagus built Amnifortis, I bet. You know who would pay well for this? The Emperor."

Grugga is especially drawn to the crystals. "What could these be? Samples they dug up?"

Investigation to identify the crystals (without handling them at the moment): 19 (rolled in game log)

Grugga beams at his intrepid companions. "Well done, everyone." He pats Leelan on the back. "What a piece of history this is!"

Religion check for signs of Cyndor, Asmodeus, Seth or some other god of labor and/or architecture: 13 (rolled in game log)

Cosette falls into the background while the boys apply their various knowledge and skills, expanding their search, disarm and discovery through what's revealed to be a museum. She hums quietly and contently to herself while taking down her own notes. She'd observe, sketch and record according to their dictations. There was plenty here for the archaeologist to take in, fill in, and appraise.

As everyone expanded their investigations, Cos considered her own. There was something about that razor thin wire above that was curious to her. While it could simply be nothing at all, she considered following it to see if there would be anything worth noting. Beyond that, the water level display pulled at her sailor's soul. It drew her in, specifically, the compass. She'd grab a chunk of rubble/rock that looked about the same size and weight, then reach for it.

Rolls if required:

The statues in the room are stunningly detailed, the work of a master.  The bases are unsigned or marked, so whether they are the product of one of the greats, or some previously undiscovered sculptor, is unknown.  They look perfect, down to beads of sweat on the bodies of the two men working the saw.

Rohuzar, just walking around in here and glancing at things, it is easy to guess that much of it could be valuable.  Some of the tools are at least gold plated and some might be solid gold.  In addition to that, all of it is ancient imperial history and could conceivably be worth small fortunes to the right collectors.  On the other hand, the fact that this is ancient imperial history is probably a problem.  Given your experience with the Empire, you guess there is likely some 'Department of Antiquity Preservation Department' that would want to claim salvage rights or seize all of this stuff outright if they got wind of it.  But perhaps Grugga is right.  This wasn't exactly part of the mission, but there is a chance the Emperor might acknowledge the discovery with some kind of bonus?  It's not outside the realm of possibility.

Grugga, most of the crystals are beautiful and stunning examples of the local geology, but not remarkable or valueable.  Two stand out.  One is a large amethyst geode, opened up and assembled for display.  The other is orders of magnitude more interesting.  It is a chalky blue crystal. 

Grugga: 

Looking over the room, the only religious symbols Grugga finds are on the statues.  The two figures with the saw, and the single figure with the hammer and chisel, all have tattoos with the symbol of Seth on their backs, the marble stained or dyed somehow to show the faint color change.

Cosette:

 As the others explore the room, none of them notice Cosette pickup a few small stones, toss them in her hand to judge the weight, and then deftly swap them for the water level and compass.  It works as planned, or else there was no trap to begin with.  The water level was once functional, while the compass is ornamental, the sort of thing that might be awarded to someone upon completion of a degree or to signify rank in a guild.

Aubrey nods in agreement with Grugga. "Indeed my friend, we might consider not removing all of these objects from here though, this might be more valuable in the state we are looking at it now. Some samples for the emperor would certainly most likely be appreciated though." The young noble says, looking around the museum. "Ancient and powerful magic has been used here..." He continues as he studies the statues. "...needless to say we need to continue with prudence, care and great caution."

Grugga sucks in his breath when he sees the blue crystal. "By Gel-Nagev..." he whispers in awe. He tries to act casual as he points out the valuable amethyst geode and the symbol of Seth, god of labor and patience, on the statues of the early imperial architects, but his eyes keep glancing back to the palm-sized blue crystal.

"I would say that you're right, Aubrey, but we've just broken down the door and deactivated the traps - I think we might have an obligation to protect these artifacts now. I leave that decision in someone else's hands, though. My only request is that I can take this crystal." He points to the chalky blue crustal. "It's not worth anything to non-Artificers and it could easily form the backbone of a masterpiece - my masterpiece - one day."

"I agree Grugga, we would need to seal off the entrance to this museum the best we can as we leave, bringing what we can easily carry, like that crystal you found. I personally don't object to you taking it but the Emperor might, and I would imagine he would have means of finding out who took what from here. That said I'm sure we can negotiate for you to keep that as a reward for your invaluable services to the empire. Whether it could be worth anything to a non-Artificer remains to be seen I think." Aubrey says with a sly smile, then nodding approvingly to the artificer.

     "Don't be forgetting our new friends,' Raqisat points out.  "I do like the concept of us taking things in order to protect them but your Emperor may not be the only one who feels they have a claim to what we have unearthed."  Raqisat casually walks into the room now that the others have fairly convincingly proven it wasn't going to explode on them and starts looking at the items more closely.

     "I for one do not plan on telling your Emperor a thing, you can trust in that.  The Rat King though... I won't be offering him any information but they're a lot closer and more likely to be trying to check our pockets," he continues.   He moves to take a closer look at the statues.  They seem perfect but are they life-sized?  Are the people all human or...?  Do they seem to be of a piece with the stands or seperate and merely place upon it.  Raqisat also examines closely the box like object the one seems to be looking through,  wondering what that could be.  He taps it with a finger as he considers it.

     "Aubrey?  Did your spy spy anything beyond these walls?  Did they try?  Wondering if we should look for hidden rooms or such beyond here..."

"Whether anyone of us chooses to divulge to the Emperor what happens here will have little consequence as he will no doubt be able to find out with the powers at his disposal. I am personally honoured to be at his service in this expedition but I have no illusions of being one of his more powerful servants, merely suitable for this mission. He has other servants who will find out what he wants to know, trust me on that. I am not saying I expect everything in this expedition to turn out the way the Emperor would prefer but I do expect him to take a great interest in what we have found here, I suppose it is up to each one of us to decide their loyalty to him but apart from you and Ms. Cosette we were all sent here by him personally, something I take great pride in as I'm sure you can understand. The Rat King though I'm not so sure he will necessarily know about this museum unless we tell him, and I suggest we don't for now." Aubrey says in a polite but firm tone. "I will let Furvus see what we can glean from the connecting rooms." He adds with a friendly smile and a nod. He then commands Furvus to peek into the adjoining rooms, using it's sight as it gets into position.

Perception: 25

Raqisat, the statues all depict humans, and they are all appropriate in size and proportion.  The bases of the statues are a different stone, but the statues are either bolted or mortared in place and cannot be moved off the base [the base can be moved, though its all very heavy].  Looking at the little device held by the standing statue, it is captured in remarkable detail.  It is a square box with a lens.  The statue is holding it up to its eye with one hand and with the other hand it is pulling down on a small knob protruding from the underside of the box.  The little lens carving is so smooth, you could mistake it for real polished glass.

Aubrey sends Furvus back through the minotaur room and through the southern doorway.

Aubrey explains to the others in detail what he has scouted through Furvus' senses.

     "I meant more is he able to travel through the walls around this room?  Or any room?  Like circle the perimeter of the room three feet deep into the wall." Raqisat explains.  "I was thinking it would be a handy way to look for hidden rooms or passages besides just peeking into rooms we already know exist."

     "As for your Emperor, I mean no disrespect.  I am sure he is a fine and honorable man. A paragon of virtue.  A servant of the people! But tell me...  If we did not tell him of this find then how would he come by the information?  At least until someone else stumbled upon it and did?  Surely you do not mean to suggest that he and his servants are somehow all knowing?" Raqisat asks while continuing to examine the statue.  Is there only one seemingly glass lens or one on both sides?  Are they seemingly peering into the box or through it?  

     "I guess I just disagree about the Rat King though.  He believes this is his territory.  I would be shocked if he didn't send minions to examine these tunnels and rooms once we return and declare them now free of the monster he sent us after," Raqisat explains.  "I've known a few strongmen rulers in my time.  They tend to be the paranoid sort and seldom take anyone at their word.  Even if we close the doors it would be tough to make it look as if we hadn't been through them.  Specially the longer it takes before we return."