yeah, i just tried that in a private match. it seems that if you face the outside of the map, keep moving right along the cliff..eventually, it will make you stop. watch for your guy to fall down just a bit (it's really easy to miss it), and then start going back the way you came. Eventually, you will fall into the cliff, but i didnt explore much past that..let me know what you guys find.
Add me if u wanna glitch together. xbox360 gt - xNemesisRebornx