Climb the stairs.

You make your way back out of the room, now with a dozen or so additional bodies of various manner of dress. You see warriors and rogues, mages and clerics. Most are adventurers, though a couple are scouts for Tanver's Crossing. They thank you profusely, but before speaking further, you urge the group to return to the upper level, just in case the Prison Princess is able to escape after all. But the moment you near the slide, you see Tenner standing there with his armour and clothing scattered all over the room. He stands naked and proud, with his arm around a satisfied Crissa.

"Hero," the man speaks. You swear his voice has gotten deeper and more confident, but you might just still be recovering from that eldritch monster's psychic scream. "I owe you my life for saving us. After everything, I have much to consider. My oath has been broken, and now I must swear fealty to something else instead. Come, Crissa. We must escape. Stay close to me and I'll protect you."

She giggles sensually as she rubs her hand over his body. "Sounds good to me~."

Regine limps closer--body recovering from the small orgasm she was given, though likely made stranger by the means of how it happened. "I'm not carrying your armour, Tenner." Her eyes turn deadpanned to Niki, and she stares at her for a time. "Hey."

Niki raises a brow. "Yeah?"

"... That felt amazing. Thanks for that."

"Oh. No problem. We're both adventurers after all, so of course I had to help."

"That's a weird response to what I just said."

"Hiyah!" Eva thrust her palm into the wall. Nothing happens. "How about... here!" The same thing again.

"Are you trying to find the mechanism to turn the stairs back on?" you ask.

Click. Just then, after a rumbling, all of the steps fold back up into place, creating a means to ascend yet again.

Eva looks over to see Xiaoqing with her finger pushing in a hidden button on the wall nearby. "B-But I'm the expert--"

"Sorry," Xiaoqing says. She places a hand on the bunny's head and strokes between her ears. "I know you wanted to find it first."

But Eva smiles with pink in her cheeks at the touch. "Mmm. It's okay. I forgive you."

Though Tenner and Crissa follow up the rear due to him having to redress himself, everybody manages to make their way back to the top, out of the smaller chamber, and into the hallway from where you first came.