To get on top of the main bridge at the start of the map, lay down directly under the edge of the bridge. Roll up towards the hill while looking at the water. You will start to see yourself flicker on top of the bridge. After a few times, you will be able to stand up and walk around. The only way to get down is to lay down and crawl backwards. You will fall to the bottom with no health damage. Note: This works on squad matches.