Here is a way you can get out of Gears of War (GOW), map Clocktower.
The tutorial was done by PlexBurress
Here it is...
1) Go to the upper lever and in the middle there is two sandbag bunkers and across from them is the sniper pickup. There should be more sandbags there. Back flip off of these and you're golden.
3) Then, if you get on the edge over looking the cars below, you can dive to the left of right and move around some more. Once you get to the sides, you can even jump down onto stuff!!
Sorry, there is no video for this glitch yet, check around soon.
Another Method video by gow97
The video below is a montage which not only includes how to get out of Clocktower, but also how to get Out of Mansion. The Out of Clocktower segmentstarts at the 43rd second mark.
