They weren't yelling anymore and that was probably for the best, but that didn't mean the feelings had gone away. Bucky was upset for a number of reasons. Mainly, because Natasha had given her life for something she wasn't even sure would work, and because she just seemed so okay with it. The idea of coming back and not seeing her there really shook Bucky to his core. She should be there. She deserved to be there. Bucky was powerless to stop her from doing it, too. He supposed he ought to be focusing on right now. She was there, she was alive, and he'd been able to tell her the truth. With that all being the case, he ought to be grateful. And he was. He was immensely grateful. But he was still angry with her and he didn't know if that was ever going to go away.
He was pushing it down right now, beneath the surface, because she wasn't budging on her position and neither was he. Natasha was right; he and Steve were cut from the same cloth in a lot of ways. Stubbornness was a big one.
"Sounds to me like that guy must not have have known what he was doing," he said, knowing full well it had been him.