the movie was amazing but i didn't get something at the end

Rating: Null/10 (29 August 2011)

i loved the movie. i think it's one of the best movies! it was really smart and the actors were great. there was one thing that i didn't understand about the end.
after the captain saved the train and stayed in that time without dying, you see Goodwin looking at his body that was lying in the source code. the body belonged to Sean who was in the explosion, they took the body from the explosion.
but that scene takes place in a time where the explosion did not happen. so how did the body get there?
l