[Self-preservation's never a bad thing; not even close. But Bakura doesn't like it when his opponents hide... or at least not when they hide in ways he can't break through. It may be hypocritical, but being a pawn in someone else's chess game is annoying. He may act casually relaxed, but someone having this level of power over him ticks him off. And what if they took the Ring, next time?

Kh, if he's the one to find the damn headmistress, he'll give her a penalty game to remember for the rest of her days.]

It's infuriating, but not surprising. What it is, is unsporting! Tch, whatever game they're playing, it's definitely tipped in their favour.