Nathan didn't think Peter was all right or okay, but he was at least heartened by Peter's response and able to let him go for now without worrying the hotel would take damage if he wasn't there. Truly, he was surprised Annie or Mantis hadn't descended into the lobby like avenging angels as Annie'd done to him the last time Peter was upset. He watched Peter leave before slowly turning back to Angela, sliding his shoulder out of her grasp as he did. His fierce protectiveness was roused, to be certain, but a lifetime of learning control was still in play, keeping that reigned in for the moment, but undeniably bubbling under the surface. The time for here-and-now pretend games was slipping away fast.
"And that, Ma, is the result of the plan you were so certain was the right one," he said, and he couldn't entirely hide the bitterness in his tone. "In November, New York blew up. I told the world it was Sylar to protect Peter, but he found out we'd known all along what was gonna happen. It destroyed the family. Peter left, never to return and Nathan Petrelli went on to fulfill the dream, follow the plan and become President. Along the way to that goal, and even after in office, evolved humans were rounded up, thrown in facilities, ostracized and villainized. Including Peter and Claire."
He stepped back, not quite pacing but getting some space. "Only after coming here did Peter finally find out Sylar had killed me and pretended to be me during that time. No one really knows when the switch happened, but they know it was Sylar because he, wearing my face," his voice caught but he forced himself to go on, "murdered Claire. She knew it was Sylar, but it's my face she sees in her nightmares."
He couldn't disguise the anguish behind those words, but he pressed on. He wasn't pulling any punches now, but the recitation of that hellish timeline still was a fresh wound on his heart, whether he'd been dead in that timeline for most of those five years or not. He'd still not done the right thing there. But he recognized that and even if she refused to see the truth about it, he'd still make her hear the results of a plan she'd supported in both timelines. This wasn't about Peter sharing the details of his past on his own terms, because he wasn't telling everything. He just couldn't have Peter dealing with her again until she knew and stopped saying the worst things she could to him.
"And you stood there," he continued, turning back to her, "and told him that the death of five million people – five million deaths he will always carry on his conscience, his heart and soul – that the five years of hell he endured, that the countless deaths after New York blew up, including mine, were all to protect him, to keep him safe."