"Oh," she echoes. It's clearly not meant as mockery. It's just a sort of acknowledgement of the whole sad, absurd situation, a kind of fatalistic sigh.

"Don't feel sorry for me, please. I don't regret a thing."

Well, almost. She wishes she could have left with Leia, in the transports with the rest. She wishes she could have stopped Dameron earlier, before he jeopardized the entire escape plan with his bravado. But for everything she did after the moment of her last goodbye to Leia? Not a regret in the galaxy.

(Unless they didn't make it to Crait, despite that. But she won't allow herself that possibility.)