Gary offers that he could shoot Owen first and then shoot Cristina and Derek, and as he's ranting he starts looking crazier and, weirdly, like he's got more stubble on his face than earlier. I guess the rate of one's facial hair growth is directly correlated to the level of insanity that's been reached. Gary just claims that he didn't come to go on a rampage, but just to make Derek pay for what he did to Gary's wife: "An eye for an eye." He again tries to get Cristina to stop working but is interrupted by the door sliding open, and Meredith walks in and tells him to shoot her instead. She then explains that she's Lexie's sister, the closest thing Richard has to a daughter, and Derek's wife, so shooting her would hurt all three of them more than anything else. Gary turns the gun on her and walks forward, seeming to think that this isn't the worst idea, actually. Cristina looks at Owen and he gives the tiniest of nods, so Cristina tries to then distract Gary by telling him that Mere is pregnant, and he wouldn't shoot a pregnant woman, would he? Gary pauses for a second and that's all Owen needs to go after him, but Gary turns and fires right at him, and Owen drops to the floor. We can't see where he's shot, and Cristina and Meredith both start to freak out. Avery then tells Cristina to raise her hands and very quickly tells her, "Trust me," before they both drop their instruments and stand there. Avery tells Gary to watch the monitor because Derek's heart is about to pump all of the blood into his chest until it finally stops beating. Mere comes completely unglued as they all watch the monitor, which shows Derek flatlining. Mere begs and sobs and Avery yells at her to shut up, with Gary all the while staring at the monitor. Cristina tells him it's over and Derek is dead.
They remain with their hands up while Mere falls to the ground, sobbing, and Gary finally shuffles out of the OR, then Cristina goes right back to work as Jackson reattaches all of the wires to Derek's chest. He's so tricksy, that one! Derek's vitals are all fine but Meredith really thought he was dead and is having a hard time computing what just happened, and Cristina finally has to yell at her to get her to go check on Owen, who is unconscious but alive. Cristina instructs her to take him to another OR and for her and April to take out the bullet, and when Meredith tries to say something Cristina points out that she's trying to save Mere's guy, so could Meredith go do the same for her? Cristina then tells Avery to remind her to thank him later, and he assures her he will. Just like with the fortune from a fortune cookie, my instinct is to end this sentence with a saucy, "IN BED." But seriously, I'm praying they don't go there next season.