1. go to the top of escalation.
2. on the left of the fountain you will see a Couple of blocks that looks like ¬.
3. take cover on the block and go right in the corner, press up so the 'climb up' image appears.
4. climb up onto the corner so that you are on top of the blocks.
5. get the 2nd player to stay on the bottom of the ¬ and crouch down by pressing down the left thumbstick.
6. Get the 1st player climb on top of the 2nd player and press A to jump onto the fountain.

P.S. If done right 2nd player (who isnt in the fountain) should of felt pain as you walked over him and after the glitch he should start to lag like a B*tch.

P.P.S. you should jump straight away when you get ontop pf 2nd player or you will just slide off-of him.

:) have fun with this glitch :D