She's probably worse off, at least for the moment, assuming she hasn't offed herself. It's a dreadful thought, but there's nothing he can do. He can't stop the train, can't turn back now, because, if she really is gone, then going back to London is just a bloody waste. Post-Deep Blue Sea.

He's going to wake up miserable in the morning, hung over and bothered by every little thing. But it won't matter, because listening to Jackie try to play the voice of reason is preferable to Hester and her nagging.