34 Actors You Forgot Were on Grey's Anatomy

Episodes: Four episodes total, between season 6, episode 24, "Death and All His Friends," and season 7, episode 7, "That's Me Trying"

That tragic case of Mary Portman (Moore). She comes to the hospital for an operation on the same day Gery Clark shoots up the joint, then when she returns months later, she doesn't wake up from the procedure and is taken off life support.