LOL, I keep forgetting about Oli as well. He's still the same size.  Not so big as to cause problems in the fortress.

"Hopefully the Speaker of Bryn Shander managed to warn the other cities that I could not reach with my sending magic." says Krom as he studies the fying path.
Noticing that Chill has opened the door to the Warlord's chamber, gesturing towards it, the dwarf adds "Shall we take a quick look? His room may hold some useful clues or informations."

If the others followed after Chill they would have found him kneeling in front of the padlocked chest.  He figured it was likely to be trapped so he spent some time checking it for traps as well as then trying to pick the lock if it did not seem trapped.

Perception 18

Investigation 23

Thieves Tools 22

Kazri asks Oli to stay by the southern door. If he hears movement on the other side, he's to come to us. (Oli Perception if needed: 8) Kazri will follow the others.

Rhogar appears hesitant at first, as ever minute spent not seeking to Xardarok felt like a gamble with far too many lives. And yet, he buried such concerns by grim logic, and quietly followed Chill into the main chamber, if only to keep an eye out for any magical signatures to warn the party about in advance of any tampering with things. 

Chill is experienced, in both the find of traps and their disarmament.  He easily picks the lock and opens the case which he deems is safe to do so.  However he does find that the trunk has a false bottom, likely hidden springs and jams the bottom down so as not to trip the trap.

The iron trunk contains a pair of dwarven sandals carved out of obsidian (250 gp), a quilted smoking jacket sized for a dwarf and sewn with fifty gemstones (500 gp), a malachite beard comb set with seven red garnets (750 gp), a hookah made of platinum and star sapphire (2,500 gp), and a rolled-up leather scroll with the following sequence of numbers written on it in Dwarvish:

Krom examines the scroll and translates for the rest of the group the sequence of numbers. "What do those numbers mean? A passcode? Coordinates? Something important for sure."
The dwarf murmurs an hymn of guidance as he attempts to crack this dwarven code.

Investigation 14  + guidance 3

Not a code breaker herself, Kazri glances at the runes, since she understands Dwarvish, and takes a stab at it. She shares her observations with Krom, then she goes back to guard duty.

Investigation: 3

"Hmm... Could be the key to stopping the construct, or... the code to some sort of complicated vault, perhaps?" Rhogar commented on assuming the cipher is spoken of aloud by its finder. But nevertheless he say once the others appear done messing with the trunk, "If there's nothing more to consider, best we be on our way below to deal with Xardarok and forces. A shame that there were no floor plans to be found. But, we've made due once before and shall do so again."  With that, he'd look to hopefully their still present duergar guide and signal them to lead on to whatever access point would bring them closer to their target.

Chill grins as he hears the soft click of the lock opening.  A quick eye also spots the false bottom and deft fingers keep the trap from being set off.  "Looking at these numbers I would agree with Rhogar, some sort of set of codes for another vault perhaps.  I don't see anything around here that they go to.  Let's take this stuff as payment for the damage to Icewind Dale that dragon will do and keep going."

Despite your attempts to understand what the 3 digit codes mean you have nothing to relate them to and so have no understanding of what they may be used for.  But they must have some importance, to be kept in this locked chest that had been trapped.

Dreck advises that in the entry room you first found him there is an elevator going down.  There is also a second elevator in a room further to the east.

The western elevator opens near the throne room and the other closer to the temple and the torture chamber.  He'll take you to either one.

Krom gives the parchment to Chill for safekeeping and then says "Considering that the warlord was torturing Harpell, our best bet to find him or her is to visit first the torture chamber. If he is not there, he will probably be in the nearby temple or within his throne room."

"I agree with Master Krom. I would prefer to find Ms. Harpell first, if possible." Kazri is ready to go to the other elevator.

Rhogar looks a touch conflicted for a moment, but ultimately and with a grim smile nods in agreement. "And if our truly holds, and we find him there, we can ambush him away from his more devoted guards... excluding any he is want to have following him about in this fortress." After a glance at Chill and Rekuberk, he turns on their duergar guide and nods. "To the eastern one then." 

"Yeah, that sounds right to me." Says Chill.  "We need to find Vellyne and if that's where she is then we better get close there than any where else. Lead the way Dreck"

You slip down the hallway and into the other elevator room.  Going down, you come to the next room. A large stone wheel next to the iron cage turns constantly. West of the wheel is a duergar encased in a cruel-looking exoskeletal construct, his face a mask of pain.

Dreck directs you north and you enter another room. Standing in the middle of the room, facing the double door to the north, is a seven-foot-tall statue of a female duergar in a scale mail robe. The top of its head above the eyes has been sheared off, making a space for a stone brazier that gives off a flickering flame. Chained to the statue’s pedestal is an emaciated, malformed creature with rubbery, purplish-gray flesh, a bulbous head with a metal plate bolted to it, and sinister eyes.

As soon as Rhogar laid sight on the pained duergar he'd turned to their guide with a look demanding explanation. But if none is forthcoming, be it due to the willfulness or ignorance of Dreck, the Dragonborn levels a pitying look at the entraped duergar... before begrudgingly moving on to keep pace with their guide. Though he'd linger a moment longer, if only to make sure any of the more sympathetic members need a little encouragement to leave things alone. For the moment.

In the next room, and assuming the rubbery creature bore no vague similarities to the group's missing wizard, both Rhogar and a peeking out Gorrah find themselves taken aback by the creature. "Who or... what even is that?" He quietly asks of their guide while refusing to take his eyes off the creature. As he asks this, he tries to search his own memories for any relevant stories from his teacher on the creature. Though with being what it appeared even Rhogar wasn't certain the Ki-rin knew of such creatures.

Nature: 16. 

Krom shakes his head as the group passes by the encased duergar muttering under his breath "That is what you get when you follow Laduguer and his treacherous ways."

In the following room, the dwarf, after giving a quick look at the statue and at its surroundings, focuses his gazes on the strange chained creature. "By the All-Father's flaming beard, what is that thing?" 
Krom tries to remember if such creatures were present in the stories that his grandfather used to tell him when he was younger.

History 19

Chill slips his rapier from its sheath and takes a closer look at the encased Duergar.  He even lingers for a moment if the others move on to the next room.

Kazri was about to ask about the encased Duegar, but after Krom's comment, she closed her mouth. She covers the groups back with Oli next to her.