Indicated spot has no collision on the ground. Area is large enough for player to fall through, and deep enough that I had difficulty getting out before I grabbed some nearby trash and dropped it in the space. Allows access to a huge area under the map, not sure how large exactly but definitely out of bounds.
Unrelated to the attached picture: I can occasionally hear loud, rapid, metallic, clanging sounds in the base. It sounds like something is somehow getting stuck in the ground or a wall or whatever, freaks out for a few seconds, and then fixes itself only to happen again later. It seems to be coming from either somewhere on the second floor or somewhere out on the roof, but I can't find anything that is causing it. I don't think this is related to any specific event or entity, but someone else might know better than me. EDIT: Upon further investigation, I can hear the sound loudest--really annoyingly so--when standing in the main hallway, near all the doors to the break room, signal processing, etc. Going the second floor, it sounds somewhat quieter. I assume there is a gap between the two floors, just going by the slightly cracked grate in the ceiling of the signal room (please no spoilers if possible) so maybe it's coming from there.