Nothing is accidental with Kubrick. Of course, this will not deter anyone from seeing the movie, which is engrossing throughout and beautifully filmed. I save my Commentary on the film until the end since it depends on the plot structure. Still, for the psychologically minded, this will be familiar territory. There is no doubt however, that Kubrick aims to show us a transformation toward greater awareness in the relationship between Tom Cruise and Nicole Kidman.
Lets look at the story parts corresponding to each stage.
Descent Kubrick does not stay long in the opening stage. The Descent gets going immediately in the next major scene, the party. The major themes of the film, sex and death, are presented to us there. He is called to surreptitiously attend to a hooker who flirts with death after a drug overdose during sex. The Descent continues most importantly after the party, not that night, but the next one.