About the best you can do is what has already been suggested: concentrate on your own training, and don't let Annoying Guy's ways get under your skin. It's as easy as that. The guy isn't a mass murderer, is he? He's just annoying, right? Annoying, you can learn to ignore and live with.

Don't let it bother you that Sensei isn't dealing with the guy as you'd like, either. The more you let stuff like that grow on you and eat at you, the more it affects your training. Let the whole affair be as water rolling off a duck's back. And that includes any time the guy slides into home plate before you can touch him.