In Level 2, I'm in the underground lake area with the green water you get to from the second indoor section, right after the thief is introduced. I keep randomly dying though. Touching the water by itself doesn't seem to kill me, nor does touching the ceiling/walls -- those only do ~5 damage if I *ram* them. This does happen when I'm flying through the tighter areas but I don't seem to really be colliding with anything. I checked a few walkthroughs and there are no notes about environmental hazards in this area.

Any idea what's going on?

I vaguely remember the water there being hazardous. If something shoots at it, I think that causes explosions or harmful splashing or something. That whole area is a nuisance! Anyhow, did you try typing in the invulnerability cheat BurgerGod? Also recording a video and posting it somewhere to demonstrate this?

So it *was* the water causing the damage, the audio cue for it's just really subtle.