I don't know why some people expect him to show his power like he did to the other guy. I mean, logically speaking, he shows his power before because he was behind a closed door and it was on a negotiation situation, so he need to establish the power structure in the tower clearly. This time the situation was on public and there is no benefit in showing his power aside from making the girl shut up. It will only makes other people know his power, which in turn makes other nation more aware of him and means more problem.