Level 5: Blind Justice
With your Green Beret, run from your current position to the left, behind the rocks and set of drums, when the guard is walking away. Quickly bury yourself in the snow. When the guard comes to investigate your tracks, pop up and kill him with the knife, or wait until he starts heading back and then do it. When the guard on the left (patrolling by the rocks) moves away from you, run up and kill him with the knife. Hide his body. Kill the guard to his right patrolling next to the house and then the guard standing by himself. To quickly get the uniform, move to the trees along the right side just out of sight from the guard standing by the uniform. When the two guards move away and the standing guard looks to his left, quickly run out a few steps and then run back behind the trees and bury yourself. When he comes over to investigate, knife him. The Spy should then be able to crawl over and get the uniform. Move the Green Beret all the way back to the left side, behind the house where two guards patrol the back and right side. When the guard on the side walks away, run out and then back behind the house and bury yourself. Kill him when he investigates. Kill the guard behind the house when he moves away from you and hide his body on the other side of the house. Then next house down on your left has a guard that can easily be killed by running up behind him. Do so and hide the body.
Use your spy to distract the guard who is facing down and get him to look up, while the Green Beret sneaks up and kills the guard looking right (watch your timing with the two guards patrolling to your left). He can also then kill the guard being distracted, or he can carry the body off and the Spy can kill the second guard. Be sure to hide both bodies. Next, you want the Spy to distract the lone guard next to the building while the Green Beret takes out the two guarding the lift. You have to time this carefully with the patrols of the two guards in the middle and the four guards patrolling to your south/southeast. Watch the line-of-sight for the guard that is towards the bottom and attack when he starts looking away. You'll have time to run up and kill the first guard and then the second. Hide the bodies so they won't be spotted by the patrols. You can either kill the guard being distracted or stop distracting him, let him turn around, and kill him with the Spy. Move his body out from where it might be spotted.
Now comes the fun part. Keep your Green Beret hidden somewhere (buried, whatever) while your spy takes a ride up to the top in the lift. Once he's up there, move to the left and kill the guard when he's towards the top-left part of his patrol. Then move down behind the soldier overlooking the cliffs and wait. Here's where it gets a little dicey. Have your Green Beret bury himself on the opposite side of the house from where the tents are, close to where to patrol passes by. Make sure you do it early enough so that your footprints won't be visible when they come by. Once the last guard passes by, pop out and begin following the patrol, being sure to stay in their footprints or you'll stray into a mine. Try and stay close to the last man but don't run him over. Right when the lead guard begins to turn north, go ahead and bury yourself in the tracks. You may have to try it once or twice to get the timing right. Then wait till the patrol passes and get up and run over to the cliffs. Try and stay in the path that the guards took. Quickly climb up to just below the guard at the cliffs where your Spy is. When the three-man patrol turns around and moves away, distract the guard and have your Green Beret climb up and kill him. Grab the body and take it to the right side of the house where it won't be seen by the patrol. Have your Green Beret wait there while the patrol passes. This next part takes a little timing. Have your Spy distract the guard on the left side of the house as soon as the patrol passes that point heading north. Have the Green Beret run up and kill him. As soon as he does, have the Spy run north and distract the patrol. Make sure he distracts them so they're facing north. Hide the body where you hid the first one.
If the guards are far enough north, you can go ahead and have the Green Beret move the barrels over. Otherwise you can wait. Once he's done, run up and hide next to the house on the right of the radar station. When the Green Beret's footprints have disappeared, the Spy can stop distracting them and let them continue. Have him run south to the point where they usually turn around and wait. Distract them when they get there. Have the Green Beret knife the guard by the radar tower and stash the body where the patrol can't see it. If you haven't already, grab the three barrels and place them next to the radar station. Then have the Green Beret hide in the snow next to the escape helicopter. Let the footprints all disappear and allow the patrol to continue. When they make their pass heading north and head back south, you can put the Spy in the 'copter, have the Green Beret shoot the barrels, and then put him in the 'copter.