Revealing mistake: In the scene where Sam Neill has set the bomb to blow up the rescue ship, Laurence Fishburne comes running up to the sealed door of the Event Horizon whereupon it shakes back and forth like a stage door would.
Revealing mistake: During the opening scene, when the camera is starting to zoom in on the ship outside earth's atmosphere - the view of the crew inside zooms in quicker than the camera moving in to zoom into the cockpit.
Chosen answer: At least one crewmember is seen as a floating, frozen corpse on the bridge of the ship when the rescue crew are exploring, there is also evidence seen that a significant amount of tissue and blood have been spread around the walls in some parts of the ship, however it is implied that the original crew are in the alternate Hell dimention, if not physically then spiritually.