Grey's Anatomy isn't all cute doctors and elevator hookups. Shonda Rhimes' long-running medical drama is also packed with shocking twists. Just when you think there's no hope for a patient, a more hopeful song from Snow Patrol comes on, and you know the guy's going to pull through. And just when you think a couple is done for, a surreptitious romantic moment brings them back together. And when it seems everything is going great at Seattle Grace, (a.k.a. Mercy West or Grey-Sloan Memorial), a bus or plane or ferry crash throws everything into chaos. Or, patients walk in dying of the actual plague.The most surprising Grey's moments are often sad, sometimes ridiculous, but always unexpected. Here are some of the most gasp-inducing moments from the past 13 seasons (yes, 13!). They're still every bit as dramatic, even when you know what's coming.