During an advance screening of The Passion of the Christ I once attended, about halfway through the film, the lights suddenly came up and the film stopped. One member of the audience had had a heart attack and was unconscious. They had to carry him away on a stretcher. Then the lights went down and the film continued. All of this just added to the intensity of that film. The only other time I've wondered whether I would make it through the film alive was the first time I saw The Exorcist, as a teenager.