The Occasional Dungeon: Crypt, Ground Floor, Part 2

Here's what's in areas 1-5 on the ground floor crypt map: 1) The room is partly filled with a dense grey mist from a few inches above the ground to a height of about three feet. Oddly, does not flow or expand outside of the approximately 12' by 12' room. Anyone peering under the mist sees a wooden chest in the southwest corner of the room. The mist is acidic, doing 1d corrosion damage per turn