This was getting ugly. If the ice moving across the floor was any indication, this would only get more ugly if Angela didn't choose her words right. Granted, Nathan had known this wouldn't be easy, that 'ugly' was more than likely because of Peter's past and his mother's lack of remorse or shame or whatever term fit, but he had to try to buffer this or the lobby would end up encased in ice, if not something more and that would herald Peter having been pushed too damned far. That wasn't acceptable.
Nathan wasn't innocent in this, he never would be. He'd gone along with that plan for longer than he ever should have, despite his doubts and conscience, and if events hadn't played out just as they did, he might not have seen the light. Peter's timeline was proof of that. And he would have to live with that.
But he had done the right thing, and he'd stopped labeling the actions before that right act as something done for anyone's best interest. His mother apparently hadn't, even now, and if she continued as she was, he knew he'd need to separate them. As it was, he made his way over to them quickly, casting a quelling look at her before reaching out his hand to Peter, resting his hand on his brother's shoulder.