So I had to figure out how to handle what happens when a PC attempts to attack themselves. I decided that, if they're really serious about it, they can treat themselves as helpless and get an automatic critical. Of course, he was a rogue, so that includes sneak attack damage. Luckily, the party cleric blew her only cure crit and stopped him from dying.
Has anyone else had to deal with something like a suicidal PC? How do you (or would you) handle it?