I've only seen Tommy slap himself around when he gets tagged, and he never really tags anyone. (To my knowledge, tell me if I'm wrong.)

As for the glitched spots, Zero mentioned that it's allowed if the people in the glitched spot don't shoot the zombies away. But generally it's a common courtesy not to go in spots like that, regardless.

Another thing is that I wouldn't let them stay in there if they're the last human, I'd move them to spec.