Matt Damon has been credited with saving the life of his GOOD SHEPHERD co-star MARK IVANIR during the filming of a torture sequence. One scene in the new movie, directed by Robert De Niro, sees Ivanir's naked character held down, before a bag is placed over his head and he is covered with freezing water. And if it hadn't been for Damon's suggestion to wave a warning sign should things go too far, Ivanir believes he would have wound up dead. He tells American publication Us Weekly, "Matt told me, 'We should have a warning sign if you feel like you're really in danger. You really could get hurt with that mask suffocating your face.' "Sure enough, if Matt hadn't thought of an alert to stop filming, I really would have passed out and died. It would have been great publicity for the film, but not so good for my career!"