Not to be THAT GUY, but He actually died of suffocation. Because of the way He was hanging off the cross, His internal organs were squeezed together so He couldn't breath. He could, yes, push Himself up from the nail through His feet to relieve the pressure on His internals (which is why the Romans often broke the legs of people they crucified) , but 1. It was incredibly painful to do so, and 2. His purpose was to die on the cross, not live for as long as possible on it. Again, I don't want to be THAT GUY, and I understand it's a joke, but historical inaccuracies like that still bug me nonetheless.