If you jump on the roof of the Hideout (by climbing the barrel stack in the back yard) you can jump over the fence and run all the way off of the map. You will fall into the bottom of the skybox and still be able to move around. Load checkpoint to return to base.
Someone made a post about this, but at 308 if you are mucking about with cheat codes the guards will sometimes randomly catch you if you are holding a big object, you get the "detected" status and then they just tase you, even if you are invisible.