"Hey, I didn't do that on purpose!" Cheshire was annoyed at his assumption that she was in control of... Her. A natural assumption, perhaps, but one that was completely wrong, "Besides, I was only trying to help." He wasn't going to get that far with fake bullets, was he? When faced with spears? He had a good point, though - what if she had killed one of them? What was she going to do if she had?