Ah, you thought I meant it like... oh no, my thought was more like, leave him without water, soon he'd be desperate enough to drink the olive oil, giving him worse shits, and when he couldn't take it any more the handgranade was his way out.

Why a handgranade and not a gun with a single bullet?

Because I don't want to litter weapons for anyone to get, I wanted something that would destroy itself when used.