Wallriding

Summary
You can do this on multiple levels, but here are a few:

Ok on this level take a sniper rifle and a spectre and boost on the wall near the rocks and the spotting area for the carbine if you played it on rifles once.It will take you a few tries.Once you're on the side keep on boosting and go left.Congrats!!!!! your now on the unreachable area.Its really hard to do though.

Note: you can do this on coagulation with a spectre, go behind red base, i think, and try to boost up the slanted part of the wall. There is also a place in Containment at the back of red base where you can wallride with a spectre.

By holding A, you can do a wheelie, which will allow you to have the bottom of the Spectre on the wall.

My description may not be clear, but there is another one on Coagulation. You can do it at the red or blue base. At red base, get a Spectre OR a Ghost, and go by the rocks behind the base. Speed boost and wheelie up the wall (it may take you a few times to find the spot, but it is near the rack closest to the base. Once you are up, keep speed boosting and you will end up on a slightly slanted wall. Get out of the vehicle and you can stay on the ledge, but the ghost or spectre might fall off. You can do the same at blue base, and you can do the same near blue base where the high perch/ledge. Just speed boost and wheelie up and your set to snipe people. You may want a rocket launcher, just in case a vehicle comes up to you. Also, since you are so high at the red base sniping spot, you cannot snipe people farther than the middle of Coagulation. This spot is near the rocket spawn.

Hope you understand the instructions. Good luck!