Host or join a game online at Clocktower, then go to the middle area of this map (not upstairs). Go to the east or west area of the middle area, depending on your spawn point, and go to the larger area that is a bridge. You will see a pickup truck with a weapon in the back. Take cover on the back of the truck, in front of the bed, then wield your lancer and blindfire it into the bed of the pickup truck. Then, do a bad active reload. While bad active reloading, jump into the bed of the pickup. If done correctly, you will fall off the bridge and can run around under the map in the river. Note: This may require a few attempts.