Anna confesses in the carriage

When Vronsky falls Anna cries out, which in the general horror passes unremarked; but then she loses self-control and flutters like a captive bird. Karenin offers his arm three times. She refuses twice with repulsion, and only when Betsy's claim on her is overruled does she rise obediently and take it. Word comes that the rider is unhurt and the horse has broken its back; she sits down and sobs behind her fan while her husband steps forward to screen her. In the carriage he means to say only that she behaved improperly, and says it; he warns her about the open window behind the coachman. Expecting, and by now hoping for, the mocking denial she has always given, he offers her the escape — 'Perhaps I am mistaken. In that case I beg your pardon.' She takes none of it: she is in despair, she is thinking of Vronsky, she loves him, she is his mistress, she cannot endure her husband and hates him. His face takes on the solemn immobility of the dead. He demands only that external propriety be kept until he has taken measures.

The confession is extracted by a man who has just held the door open for a lie and is begging her to walk through it. Tolstoy gives Karenin his one moment of dignity — screening her tears from the stand — immediately before she destroys him. Anna's closing thought, that it is a good thing she spoke out, is relief rather than courage.