The film is told entirely in reverse and makes the whole ordeal much darker knowing what has happened to Alex. From Marcus and Pierre leaving the party searching for Alex to finding her, stealing a cab driver's taxi to find the club, the party itself where Marcus's partying causes Alex to leave, riding the subway discussing the difference between sex between Pierre and her current love, Alex and Marcus in bed getting ready to go to the party.
The film makes several references to what is about to happen to the couple as Alex notices that he can't feel his arm in bed and Alex reveals her dream about a red tunnel(the very tunnel where the rape takes place). The real gut-punch of the film is watching Alex find out she is pregnant knowing that she will inevitably lose the child.
Those with a queasy stomach regarding violence and rape should probably fast forward through the scenes because they really are quite brutal. Never in a film before has such thought-out real-life ramifications of vigilantism, violence and murder been explored.