"Ah!" The auburn-haired boy's eyes widened at the sight of the disintegrating rock. "So that happens to anything that flies at it? It wouldn't happen to do that to a person if they were thrown for some reason, right?" It probably went under the same category as "charging enemies," but he just wanted to be sure before he tried it. He really didn't want to accidently vaporize someone. 
...Though, actually, if someone was being thrown, it would probably be better to try catching them rather than deflecting them, wouldn't it? Hmm....