I'm still figuring out the optimal prose for this, so there will probably be some shifts here and there.
An Atrium in... Space?
The atrium is surrounded by glass panes, seemingly thicker than they look, or just apparently very strong, as outside you can see stars and nebulae twinkling just outside in vivid, beyond-real details.
Golden-brown particle streams of a vast dust nebulae stretch beneath the transparent floor, fogged by glowing whiteness that served as this room's illumination.
Glass cases of various trinkets and models are placed in the spacious room, their details obscured by the faceless crowds of NPCs in casual everyday wear, though some of them stand out to you as various characters from within your dreams.
Cinder is here, a monochrome male with bunny ears, holding an empty notepad. He waves at FallacyofUrist, and presumably anyone else present.
"Hi! Thanks for participating in this experiment. As you can, uh, see, I'm not so great on details right now, but hopefully we can improve that as we go along!"
He flipped through the empty notes for a bit.
"I really should've prepared some surveys and actual notes..."
He jerks a laconic thumb to a pair of large, glass sliding doors that have totally always been there, leading to another room.
"Anyhow... that's the entrance to the, uh, museum I guess? I'll be generating details on various dreamscape demonstrations as you guys explore. Try to keep track where everyone is, so that multiple people can interact. Also... I think it would be more immersive if we used walkie-talkies instead of telepathy..."
He waved to the receptionist's table, which was actually unstaffed. It just has a big pile of nondescript walkie-talkies on the table.