Ok, so Megatron came back to life in ROTF via Allspark Fragment. Now if the Allspark Fragment is anything like the one from Animated, the shard should still keep him running even after what happend to him in DOTM? Which also could be why he survived his mortal wounds from ROTF. Though there could be the possibility that Optimus yanked it out of his body, but unless they put that in the story the possibily of him staying alive could still remain open. Or am I wrong?