See, Rocket was up on the roof off-loading a patient from a helicopter when he raised his arm to wave, and the helicopter's tail rotor severed his arm just above the elbow. They tred to reattach, but it was ultimately unsuccessful.
A season or two later, he was out in the hospital's courtyard when a medical helicopter fell on him.
Gotcha. Wife was still watching it around then, so I just remember bits and pieces.
...perhaps that wasn't the best choice of words.