Obviously you haven't ran into the bullet curving magic this game has either.
Where when you're getting shot, retreat behind a wall and are 5-10 feet behind that wall then all of a sudden you die. It's not even them shooting through the wall, it's the magic curving bullets.
i saw this in a kill cam yesterday except there was no cover involved. guy is shooting but the enemy was 3 feet to his right and the bullets hooked right to him while the barrel of the gun never moved.