As they say, why go in through the front door, when you can go in the back? Of course, going in the back door isn't always the best way, but in this case, it is the best way. Take the high ground when you can. Notice, I quickly dispatch the 8 guards defending the passage up the mountain. Three fall to the silenced pistols, at least 2 fall to the grenades, and another 3 fall to the AK. I heard the last guy, but I admit, he did surprise me a bit. Of course, that means you just get to deal with him earlier than you expected - he is quickly dispatched.