3x16 Drowning on Dry Land
At the disaster scene, other rescue workers find the man with the injured leg at the edge of the dock. He's got Meredith's tag on him, but she's nowhere to be found. Derek assumes she finished with him and moved on.
George lies to the mother whose son is missing that he's found him so that she'll consent to go into surgery. Miranda insists he really find the boy by the time the mother wakes up.