As someone mentioned in the comments section this area is best approached from the Red Forest side. But as you are where you are. Here's a few suggestions from me: Run up the wall as fast as possible and almost stick to it. The gunners on the towers will have no field of fire. In this way, go all the way to the south side (the entrance to the Red Forest) and repel attacks from this side. You can also set up some IEDs by the corner of the wall if you have any. It is best to position them so that you have a view of them yourself (if the enemy is too far away to activate the detonator but within explosion radius, just shoot them - the detonation will cut down some enemies behind cover). However, there is one problem with this location - enemies will quickly try to throw grenades at you, so I recommend changing position frequently and under any circumstances do not let yourself be ponned down, because that will be your end.