At the start of this, I was annoyed at how difficult is was to picture the exact layout of what was going on with this. It's like, I got some idea eventually, but I almost got it in spite of the description.
That is, there's a trapdoor… that leads to stairs or a ladder? Or does it alternate? Are the stairs inside of what that structure's bottom story would be, or are they on the outside like in picture? Is there a trapdoor on every level? Does the trapdoor go straight to a copy of the glass room or are there stairs in between?
I don't have much comment on the rest of this, which was quite neat, although the last bit had a "writing" instead of "writhing." I recently dinged someone points for writing a video log in purple prose, which I'm a little iffy on here.
(Oh, also, why the cognitive test instead of/in addition to giving the dude a barometer?)
The bum description just really wrong-footed me. (Edit: I'm not even saying I want more detail here. A minimalist description is fine if I can picture it.)