How do I escape the cell? (Fighter)

Hint 1 of 5:

Come on tough guy, you can't think of anything?

Hint 2 of 5:

The lock doesn't look that strong.

Hint 3 of 5:

Maybe you could simply use your muscles and push your way out.

Hint 4 of 5:

What's the matter?  You fail the first time and you're already back here for
another clue?

Hint 5 of 5:

Gimme a break.  Try hitting the door again.