Taboo
They've talked over almost all of it, everything that happened to leave him (almost) dead and (almost) reduce her permanently to a legal secretary.
How else are they going to pass the time when they wake up in the middle of the night to one of the pipes exploding and by the time they've got everything cleaned up they're both too wired to sleep again?
But there are still a few things they steer around, trying to be subtle but both acutely aware that there's something there, and aware that the other is avoiding it too.
Specifically, he doesn't want to bring up his throwing her carelessly to a man half-mad with grief and fury, because he knows she's probably still angry with him, even though he tried to explain that he had it under control, would never have done it if he thought she was in real danger.
And really, she has no especial desire to hash out the issue of her response. She knows that he considers her unrepentant show of treachery and defiance, releasing that man and then helping him and his family to escape, a hell of an overkill. But she wholeheartedly disagrees, so it's safer not to bring it up.
Of course neither of them really believes it, but for the sake of keeping the peace, they come to the unspoken agreement that they're even now.