It was a threat that he'd expected, and he accepted with a nod. It was a common parental thing to say. The fact that he was sure that Jo would go through with it didn't really add any fear to him. Mostly because that's the way it should be.
Mary appearing was nice, though Johnny had no idea if it would make the situation any better, or just turn up the heat under the pot of crap he was already swimming in. He thought that he was getting his points through to Jo, if they added a third hothead to the mixture, it might explode.
"It's okay." He smiled at Mary a little. "I think she's done."
Johnny tried to not bring attention to his slightly swollen lip. At least it would likely fade before the afternoon, given his healing rate.