Finn gives a health update on Doc, Meredith is assigned to work with Callie for the day while George gets paired with Derek, and Burke and Izzie continue to try to find a heart for Denny.
In the stunning conclusion of a two-part episode, Meredith furiously works to save the life of a paramedic trapped inside an ambulance, as her sister, Lexie, holds the life of a patient in her hands.
A dangerous situation leaves the doctors fighting to stay alive while trying to save their peers; Ben and Bailey make a decision; Teddy gets a tempting offer; Richard plans a dinner for the residents.
While Meredith faces the repercussions of messing with the medical trial, April tries to step up at Chief Resident; Cristina and Owen disagree.
The doctors form two teams to operate on conjoined twins; Bailey uses Meredith as a buffer between her and Ben; Alex learns a tough lesson; Teddy asks Cristina about Henry's surgery.
