He folded his arms over his chest, but loosely enough so that he could reach out and grab Sherlock's hand just in case. Yeah, Sherlock wasn't doing a very good job of convincing Yamato that he was going to be careful about this experimentation thing.

"Can't you just assume that nothing's changed? I mean, it's not like your tolerance has suddenly gone up, right? You just can't feel it." Logic, Sherlock. He may not be as good as you, but hey, the Japanese school system has drilled enough of it into him. Having to make sure Taichi didn't do Stupid Things also probably helped.