[Schimid]

No idea about the system or anything. I could SWEAR it was in Psychonauts, though. In the Milkman level...but I don't think it'd be anything that dark.

I might be wrong here but I think there was something else you put into the pool first; to deactivate a bomb or something harmful. And after that was blown up, you can go in and grab the item and when you try to leave, everything goes nuts.

It sounds very Silent Hill-esque. It very well might be that.