On the toilet
The way in which the movie starts is a bit ironic. the song used in the beginning, as well as the clothes the characters wore and their behavior wanted to leave the impression that the characters were members of the high-class, cultivated people who were educated and knew how to behave in a social situation. Despite all this, the second frame in the movie shows the main character, Alice, sitting on the toilet while her husband was getting ready to leave for a party they were invited to.
Everyone is a stranger
After arriving at the party, Alice and Ben go to the ballroom where they start dancing and talking to one another. From the way the two were welcomed by the organizer of the party, one would be inclined to believe that Alice and Ben were popular among the group of people they associated themselves with. Bill notes however ironically that they do not know a single person in the room and that everyone is a stranger for them.
Saving her and saving him
While at the manor, during the sexual orgy, Bill is told by one of the girls that he should leave because he is in great danger. The woman who tried to save him was Mandy, the girl Bill saved in the beginning of the novel. Ironically however, she is killed for her efforts at the end of the film.
Refusing to cheat on
Alice expressed her desire to cheat on her husband to him one night and the revelation shocked Bill. Despite admitting that she wanted to cheat on Bill and despite the fact that she had time and a person to sleep with, Alice refused to cheat on her husband and decide to remain faithful to him despite her desires.
Not so unknown
The reason why Bill wanted to go to the sex party held at the mansion was because he hoped that his identity will remain unknown. Ironically, he is recognized by at least two of the people present there and one of the people possibly died because they recognized him.
