how does svidrigailov trap dounia, and how does she react in this crisis

Svidrigailov writes a letter to Dounia explaining that he has answers in regards to rumors circulating about her brother. After she meets with him, he tells her that they must retreat to a quiet place to talk. This act, of course, is an attempt to have sex with her. Svidrigailov tries to keep Dounia from leaving, but she fights back and even (non-lethally) shoots him with a revolver.