When the level begins, your partner leads you to a rooftop perch and instructs you to snipe the guards in the courtyard below. He’ll mention that the best strategy is to start with the roof, then take out the towers and finally the patrolling guards on the ground. The rooftop guard is literally straight ahead just above the floodlight. There are two tower guards, and it is advised that you take out the tower on your far left before taking out the obvious one right in front of you. After that there are 5 patrolling guards on the ground, check near the torches and campfires to spot them. Once all of the guards are dead, your partner will then separate from you and you’ll move ahead on your own. The level is a fairly linear path and it is advised that you switch off lanterns as you go to avoid being spotted. Also, keep in mind you are outdoors and wearing a gas mask, so be sure to scavenge for filters, especially from downed enemies.
Take the nearby zipline down to the next building and wait for the two guards to finish their conversation and move to their stations before taking them out. Go through the red door opposite the gaping hole one of the guards was peering out from and drop down the broken stairwell.
Soon after, you will come to an area that has a series of catwalks. If you look straight ahead, you’ll see two guards talking to one another. They never move, so ignore them. The first catwalk that goes off to the right has a guard stationed at the end of it, so take him out. Follow across the catwalk and then take a short jaunt left to find a ladder leading up. At the top, you’ll begin taking damage from the extreme weather, so quickly duck into the building that is straight ahead of you.
There are 5 guards patrolling this building, so find them and take them out. The last one you will find is standing guard next to a ladder that leads up. There is a second ladder on the next level leading up again to a ramp that allows access to the roof of the building. Once on the roof, look for the raised platform that has a zipline running down from it. DO NOT take the zipline yet.
Looking down in the direction the zipline will take you is another courtyard filled with guards. Take out the three tower guards first, starting with the one on the left and working around to the right. There are 7 patrolling guards on the ground, several of which are solitary and can be sniped easily. However, there will be two sets of guards that are close together and can see one another. One set will move away from each other, and this is when you should snipe them, but the other set remains stationary, so quickly snipe them both in succession before one of them can raise an alarm, or make them your last two kills. Once all of the guards are dead, zipline down and make you way to the back of the compound. You will find a tunnel leading down to a closed door. Open the door and enter to end the level.