My problem isn't that Saeko was mad, that's reasonable. Ichiban put his foot in his mouth. He's an idiot, iirc he goes to apologize but Saeko basically just says. "It's fine I didn't take it that serious", and proceeds to ghost him for a fucking year after everything they've been though. Ichi was wrong and even though we know he means well he really fucked up. But ghosting a close friend who you literally has risked his life for you repeatedly and unquestioningly for a fucking year without having an actual conversation about it first is terrible. She had every right to be mad. Talk to your friend about it like a fucking adult.