Trivia: The film was primarily shot on "prosumer" grade digital camcorders due to how fast and cheap they were and for the visual style. This is part of what gives the film its unique and extremely gritty visual aesthetic. In contrast, the final scene was actually shot on proper film to give it a much cleaner aesthetic and a sense of finality.
Trivia: The dramatic pause, as the taxi hits the gate near the end of the film, is done so because this was the original ending. Test audiences didn't like the ambiguity of the ending and wanted something more succinct, and so we got an ending-like sequence followed by the actual ending.
Trivia: Mark was likely not infected. The wound on his arm was clean-cut and probably from either glass or a weapon wound. A bite mark would look very different. It is likely that he asked Selena to wait because he was scared and knew what she was like.
Answer: Jim's parents did not get infected with Rage. They decided to commit suicide, hence the pills and alcohol beside the bed. They basically decided that it was better to die than become infected, hence the message on the back of the picture. Those that are infected with Rage, the length of time it takes to die probably relates to how they were infected. If they were infected through the mouth or something similar then they would live for a while, if they were infected through a serious wound then obviously they would become infected but would not live as long because of the serious injury.
Tallicame