Skeet Ulrich was really in pain when he was stabbed in the movie Scream!
In the movie Scream, the villain Billy Loomis convinces his friend to terrorize their high school and murder their friends. To make the killings look convincing and throw off the police, he and his friend stab themselves. In one scene, Ulrich was wearing a protective suit for filming so that he could be stabbed, but not really harmed.
In the movie, he yells as if being actually stabbed, and the reason for this is because the blade missed the protective suit and actually struck him in the spot where he had recently had open-heart surgery! Ulrich was in severe pain yet continued shooting because it made the scene look more authentic. If that isn’t dedication we do not know what is!