much like everyone in the replies i kinda rly wanna know what the fuck this place is so heres everything ive gathered from the video:
from what ive been able to guess, i think this is something like the inside of a cold storage or industrial facility of some kind. at the beginning of the video the plane of the door appears flat, but as the camera goes through it, you can see the wall and doorframe angles up and away from the viewer. it could be a single-faced angled wall, but to me it feels much more like it's a part of a dome.
the internals being that foggy are by design, i'd reckon, though what the purpose is i cannot say. oval-doors are used on naval vessels to make doorways water tight, which confirms to me that this is definitely an interior shot. my best guess is that the metal walkways are there because the floor of the room is supposed to be a pool for water. that would explain the intense condensation, as the more i thought about, the more it seemed like it looks like that because the fog is accomplishing something intentionally.
based on the deterioration the railings are showing, i'd also say that the fog has been going for quite a long time, and is therefore likely not toxic since the railings and relatively low security door imply that this place was walked through frequently. to me, this seems like an important detail to notice because that would mean the water is likely non-toxic. theoretically it's chemically benign and not radioactive, which i think would rule out something like "missle silo" or "fission power plant".
beyond that, i'm at a loss. and all of this might be wrong anyway, but i sure enjoyed Deducing for a bit!
