The ending seems to be very forced and doesn't make any sense.
1. Seligman is supposed to be asexual and the point was made that he was not sexually excited at all while listening to the sory. Then in the end he somehow wants to have sex with Joe, just because Von Trier said so. But he couldn't have asked to have sex with her when they were talking, too?
2. There was no reason at all for Joe to shoot Seligman, simple "no" was perfectly enough. He wasn't violent. She was so grateful she didn't become a murderer only to murder Seligman, who helped her and listened to her?
It felt like Lars Von Trier gave a middle finger to the audience by this ending.