It was one of the most shocking things to happen on Grey's Anatomy, ever. After falling asleep watching surgical films, Cristina is snapped back to consciousness by her boyfriend, Owen, ruthlessly choking the life out of her. She struggles with him for what seems like minutes before Callie finally bursts in and Owen snaps out of his trance. Cristina tries to stand by him, knowing that it's Owen's post-traumatic stress disorder that caused the episode, but she can't. And Owen, confronted with losing the woman he loves, finally accepts Derek's offer for help with his treatment.