Perspicacious, can you roll either stealth or slight of hand to read it surreptitiously? 

Your DC is... Perception: 15

Sleight of Hand: 5

(Marvelous)

Perspicacious, though you can't see its face, you notice the gaze of the creature in the purple robe pass between your unbound hands and the manacles you've left behind as you follow Amaruve's large form into the hallway. You wait until you are well away from it before quietly opening the paper in front of you. The light is quite dim, but your Tiefling eyes have not lost their acuity- you can read the note plainly. 

On it are written two words in a small, simple script: Tonight. Bridge.

Jean, charged as you are with Perspicacious' protection, you are duty-bound to follow her into the hallway (which I assume you do)

Amaruve, the passage is a little tight, but your ribs don't quite scrape the bare stone walls as you pad past them. To your bear senses, the air seems stale; this obviously hasn't been used recently. (Normally, I'd have you roll perception, but for the sake of moving things along:) You notice that the floor is sloping very subtly downward. Though you've only been walking for a few minutes, you would guess that you are now 2-3 stories underground. The light is getting dimmer, but you're still able to make your way without trouble.

Gordra and Cordelia make up the rear. The man in black is just ahead of you and the purple-robed creature is just behind. You leave the unconscious Thunder Stein woman on a bed in the medica, and the hidden doorway swings shut behind you.

The Pretender (who hasn't yet offered any other name) maintains a steady flow of chatter as you all walk. "Oh, yes, these passages were a fantastic find. Really game-changing, if you know what I mean. Of course they expect so much from my lab; I find that I have little more freedom than any of you do, including our hobgoblin friend up there. Ever since the last war ended (if you can really say that it did)... Yes, just keep going straight up there, my furry friend! We'll get there soon." 

And on he continues, describing in great detail how overworked he is, how he has been developing his arcanobiological creations for the ongoing war efforts (though the government is not calling it that), and the arena, though ostensibly just a salve and entertainment for the populace, is actually a testing ground for his constructs. 

I would check the readings on the DST as we walk, seeing if they have change as we travel.

Amaruve, Jean, and Perspicacious- just as the man calls out, you notice that the hallway splits to the left and the right. The passages to the left and ahead of you are much wider and taller. You can go straight, as directed, but you detect fresh air and the sounds of the arena air coming from the left. You see a bolted iron gate several feet down from the intersection to the right. 

(Turning control over to you all- what do you do?)

Quote from Shaz_Mazoo >>

I would check the readings on the DST as we walk, seeing if they have change as we travel.

 Gordra, familiarized as you are with the Local Potentiality feature, you see that it is moving around the 50% mark- sometimes jumping a little higher, sometimes a little lower. 

Silently Jean indicates the different directions to the others and gives a questioning shrug.

Gordra will stop in the middle of the intersection,"Mr. Pretender, where are we headed exactly?"  

Amaruve, having continued straight, stops and turns awkwardly in the narrow hall at Gordra's question. He looks to the pretender with a tilt of his head.

Amaruve, Jean, and Perspicacious, can you roll perception for me? Amaruve, you have advantage here.

Perception: 17

(That's good enough!)

Perspicacious, in addition to the sounds of the arena to the left, you hear a snort and a low, pained moan coming from behind the locked iron gate. To bring everyone together, you could try to covertly peel off and check it out, you could just continue on with the group, or you can try something crazy. Amaruve, and Jean- you have the same options

Perspicacious will continue with the group for now. Hoping to find time to discuss the paper and their predicament at length. The moan and the snort are probably just another gladiator combatant in need of attention.

If the guy doesn't answer my question and everyone keeps going I'll follow.

"Why, to my lab, of course, Mr. Porter"

He leads you past the intersection and into a large open cavern. This space is largely empty. There are a number of empty glass bell-shaped tanks lining the walls, and two similar tanks perhaps twenty feet from the door are filled with an opaque green liquid. These tanks rest atop purple insignia that burn with an arcane power. A very large empty tank rests in the exact middle of the room. A great deal of green liquid lies in still-steaming puddles around it. 

There is a small alcove in one corner, and The Pretender leads you to it. A small sitting room is there, complete with desk and a large couch. You notice that there are two other openings to the chamber.

(I promise that things are about to get interesting again soon! Non-combat scenes are typically your chance to find out what, exactly you need to do get out of a world!)

The Pretender looks just a tad embarrassed. 

"You'll have to excuse the state of my lab. I'm afraid that the," he glances at Ritz, "the bulk of my assistants have gone topside to drown their sorrows in ale and one another's company. They worked tirelessly on the ida-ke, you understand, and to see it erupt in flames... Well, I won't begrudge them the evening."

He gestures for one or more of you to rest on the couch. "Please, make yourselves comfortable. I'm sure you have questions for me"

Amaruve goes and plops down on the indicated couch, which groans audibly under him. He doesn't seem to notice.

(Did we receive the benefits of a short rest in that last hour before the pretender arrived?)

(You have a long rest coming up (unless you all do something completely unexpected), but you were healed by the cleric and had time to recover a single spell slot.)

Amaruve- you take up the entire couch (and then some), which is the only seating in the room