F: While the liquid is draining, check what was in that room the crawlspace led to
Upon entering the room you quickly realize it's not a room but a long hallway that branches off to the left and right every so often. There is a SAFE in the wall to your left and in the closest hall exit you see 1 (ONE) LARGE KEY and what appears to be someone's feet. You can't see anything else from this position.

F: Eat wall to make hole larger