Glitch To Get Of The Map
First you get a monster or a racer note lancer does not work you go to that pillar with the car on it by there is a drop you drive off it then hit y you switch to gunner and the screen will be red switch back and drive off map.
Secret Armory Exploit
After you defeat General Knoxx, continue to the armory. Once you enter the color code you'll enter a hallway. Continue down this hall way a little bit and you'll see that there is a metal spacer on the ceiling and walls, where there looks like a door should be. You're right. This is, in fact, a door. Once you see this, walk over to the right side of the hallway, next to this door. Now crouch. If the glitch works correctly then you should fall through the floor and land on a pipe right above the armory! Since theres no falling damage you can jump down and start opening Gun Boxes! With no time limit! BUT! DO NOT! Pass where the elevator would be! Although the elevator is still above you, if you go into this area it will check an objective box and you will NEVER be able to return unless you start a new game. So enjoy! You can open all Gun Boxes, theres no time limit, and you can exploit this glitch as many times as you like. If the falling through the floor doesn't work the first time, you might have to move up to where the next door should be. Have Fun!