Go to where the Torque Bow is found (on default weapons), then take cover on the wall away from the train tracks and run back and forth on the little "C"-shaped wall part until you "pop" up. Press A to get off the wall, then walk along the "invisible" wall away from the level. Do not worry as you cannot fall off. When you go back slightly, you can see to your left or right (which ever side you went on) behind the rocks. Go to one of the giant pillar objects and tap A in a diagonal direction to dive. You should get through. If desired, you can get through to where it is all black. You will fall for about a minute and end up on top of the grenades, and thus will die.