Vronsky stresses to Anna that he thinks she should confess everything to Karenin and leave him. Anna does not want to run away, however, because she does not want her son to have a mother who abandons his father. Anna hears Seryozha returning, kisses Vronsky goodbye, and tells him to return at one that night.
Vronsky thinks only of what would be best for him, that is, that Anna run away from her family and join him. Anna knows that the situation is much more complicated, but she still wants to maintain the secret affair.