1) The horrific plane crash. In one of the more shocking finales in the show's history, Mark, Derek, Lexie, Meredith, Arizona and Cristina find themselves stranded in the woods after their plane crashes on the way to Boise. Lexie dies after sustaining serious injuries from being crushed by the plane. Derek's hand is severely damaged, leading to a lengthy recovery. Mark dies after they're rescued. Arizona's leg is amputated. Cristina suffers emotional debilitation, which causes her to move to Minnesota upon their return.