First you must go to the basement and find the floating crate push B to grab it. Take it in front of the shooting gallery door. Push B to let go of it and open the door grab it again. Take it through the glass door where you shoot. Turn around while holding onto it and let go of it while the door is open the door shouldn't be able open now. Then go to the computer and push B and pick any gun. You shold now be able to shoot anybody or anything outside the shooting gallery. Using rockets and grenades you can make all of the lights go out. If you shoot the guns in the displays they will disappear. You can shoot outside of the door but if you go past it your gun disappears.