TMB40,662 Locked 24 Dec 2016
I got this in the first mission. Right after you get down to the streets from the roof, take out all the enemies in the first area. Now, there is a guard standing still facing away from you at the bottom of the road leading up to the next area. Position yourself against the blockade (the one with the health potion on it) and save your game. Then start sprinting, crouch to slide and fire away. Got it on my second try this way!