There are spots, many many spots, where one person can shoot you, but you can't shoot them because there is less than a millimeter of body showing and anytime you shoot, you hit the wall. Can this be fixed? Not drastically nerfed, just, shootable.
I am the Pillar Of Light in a Land Of Darkness.
If I see you first, you die.
If you see me first, you die.
Bottom line, you die.
One spot like this is the left-side staircase (from the attacker's perspective) at Point D on Markov Station -- that is, the side without a subway train.
This is a known problem I think, and it has to do with being prone on inclines. Players should not be allowed to go prone on inclines, if they try it should put them in a crouching position instead.