*SPOILER*How is Xavier walking in the end of "Wolverine: Origins" ?

X-Men Orgins: Wolverine was a prequel in continuity with the X-Men trilogy. They were going to make another origins story for Magneto and probably others. Scratched the idea, probably because it would be a lot of movies to make and they had to make a lot just to make the Avengers. So, X-Men: First Cl was made instead, sort of an origin story but not in continuity with the other X-Men films. Hence Mystique being a different actress, Cyclops's younger brother somehow being around Xavier's age, and hence them being able to make Beast and Mystique coupley despite them having nothing together in the other movies (plus, Mystique a in the comics and not an X-Woman).