Charles has to tell him twice, but he’s confident enough that Erik will do as he says that Charles doesn’t even begin to reach for his temple.
This scene is such a wonderful example of Charles’s optimism and faith in people. (This and when Beast flips a bit and starts choking Erik (Charles, why do mutants choke other mutants when you’re around?)) He’s fully capable of stopping them, but he doesn’t force it because he’s certain they’ll do the right thing and not kill someone. It’s rather saddening that he’s proven right here, that his faith is justified, but that later, when there’s so much on the line, is when he’s wrong.






