X-Men 2 (2003)

Continuity mistake: In the end, when the President is visited by the X-Men, he receives a blue binder, which is laid in front of him on the table. When they have left, you see a shot including the President's desk, and you can see that the only thing he has on the table are some sheets of paper, stapled in the upper left corner, opened up. Then the shot changes to a close-up of the President, and then back again, and you see the blue binder in front of him, closed, and the papers have disappeared. (02:01:40)

Policeman: Put the knives down!
Wolverine: I can't.

Trivia: The young girl who runs through walls and soldiers when the mansion is attacked is Kitty Pryde, aka Shadowcat from the comics. She is also referenced in the first movie, as "a girl in Illinois who can walk through walls." (00:33:20)

Question: Why does Charles look out of the window in the end of the movie, when he's teaching a class?