After Dunya's departure, Svidrigailov indulges his low, vulgar taste in entertainment places on his way to Sonya's room, next door to his. He tells her that Katerina's three children are very well taken care of. He then gives her 3,000 rubles for her own use. When she tries to refuse, he tells her of Raskolnikov's two alternatives — either a bullet through the head or prison in Siberia. There is only one qualification for accepting the money; she is to tell absolutely no one where it came from. Also she should take it tomorrow or as soon as possible and deposit it with Razumihkin.
Svidrigailov continues on his way to see his 15-year-old fiancée and leaves her a note for 15,000 rubles. Returning now to his room, he dreams of finding a young five-year-old girl whom he picks up and takes to his room. In his dream, this girl suddenly grows older and assumes the role of a depraved French prostitute. Svidrigailov then gets up and wanders to the park where he takes out his revolver and puts a bullet through his head.
After Dunya's declaration that she could never love him, Svidrigailov realized that he needed more than sensual pleasure; he also needed human warmth and affection. His entire life was based on the theory that he was completely self-sufficient and self-contained, that he needed no one, that whatever he wanted he would simply take and ignore any consequences, and that his will was stronger than anything else.
Suddenly with his realization that he needed but could not will the human warmth Dunya could supply, he saw the failure and sham of his previous existence. With this insight, he simply cannot return to his previous mode of existence, which he realized to be false. Likewise, he cannot change. The only thing he has not willed so far is his own death. Immediately after these realizations, he has the dream about the little girl he picked up and who, under his touch, turns into a shameless whore. Thus, these realizations lead him to his suicide. Svidrigailov feels there is no other choice for him except to will his own death.
Svidrigailov's suicide is part of Dostoevsky's thesis that no man can set himself apart from humanity. There can be no superman, no Ubermensch, who is allowed to transgress the law. Sooner or later, every person needs human warmth and companionship.