"Look. It's not my proudest moment. And yet..." Peter shrugged. He had his regrets, sure he wished things had gone differently. But he'd been distraught. He'd just found out...well, he had reacted out of a place of raw grief and despair. He wouldn't apologise for that.
"It happened, all right? It's over and done and I can't take it back. I can't change the outcome." That was about as close as Peter would get to admitting he'd made a mistake.