First of all create a new multiplayer game in which your shields and life are the maximum they can reach. After creating this go into the game and also go into the level Sidewinder. When you are in the level get a rocket launcher and plasma grenade, and travel to the Blue Tower Base. Go to the top of this base and then go through the teleporter. When on the other side keep walking until you are around the bend. When you get to the end of the bend there should be another room with a teleporter in it and from the outside there is a border to the room in which you can jump on (looking at the room from the outside!). It may take a few tries but you will get up there (you can also take a vehicle up there with you for easy access to the top of the border). Once you make it up onto the border go to the end of it and looking down slowly walk backwards and get a grenade caught on your foot. As soon as you get the grenade on your foot shoot the rocket launcher down at your feet. The lift should send you flying pretty high. When you first start flying through the air push both joysticks in the dirrection of the wall that you are attemting to get upon. This may take many tries, although it is very frustrating once you get the hang of it, it can be much fun.