This is definitely one of the tougher missions in the game, especially if you’re trying to do it without being seen or killing anyone. As for which Buddy to bring along, since you’ll be dealing with a lot of enemies with helmets on (especially if you’ve been going for headshots throughout the game), it might be better to use D-Dog. This is because there are a lot of enemies in the mission and knowing their locations will help immensely.

There won’t be any enemies in the first area where you get out of the helicopter, so just run until you reach the base, where you will likely notice a sniper. So, if you see the white warning sign with a crosshair, hit the dirt and crawl along. In addition to the regular enemies and snipers, you also have to contend with ones that are using Walkers.

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The entrance (left) is heavily guarded with walkers, snipers, mines & heavy infantry. Crawl far away from enemies to make it to the base (right).

You will also have to deal with a gunship, which you’ve probably seen on your map, but it tends to stay in the third area, provided you don’t get spotted beforehand. As you approach the base, it’s a good idea to crawl along the right-hand side, then start moving towards the first gate. Head through it and once again, go to the right, where you’ll pretty much see no enemies over on this side.

Upon reaching the third area, you will now have to contend with the gunship, as well as enemies in Walkers and other normal ones. This area has some buildings you can enter, but they are dead ends and don’t have another exit besides what you use to enter. So, go around the one side of the first building and then around the side of the next to reach the back end of this area.

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You can also sneak to the helipad by cilmbing through this window (left) and sneaking up to the gantry level through the hole in the wall (right).

Sneak past any guards here and climb onto the stairs to reach the final area before the end. Using the tank as cover, crawl along the right side and you should be able to go by all of the guards, including the Walker by the exit, without being seen at all. Once you get there, there will be no more enemies. Use the stairs to eventually reach the heliport and you’re at the finish, only having to follow the linear path to a lot of cutscenes.

Mission Tasks

It’s best to go after all of the optional mission tasks in one go, since they will require you to do a lot of extracting. Each section of OKB Zero will have one guard in a Walker Gear. Past the first gate will be one tank, then you will find the second one in the big area and the third will be in the last area. As for the containers, there will be four past the second gate and the other three past the third gate.