Thief Side Mission: Check, Mate

Climb the crates by the two men huddling around the fire. Open the window, loot everything, then head downstairs. There's a switch on the wall that you can shoot with a blunt arrow, or slowly sneak up on. As you can see in the video, I've become to jaded to even try to pick the lock with the man in the room.

After you pick the lock and enter the next room, there's a door to your right. Enter, and use focus to find the electrical box. Cut the wire, and you can freely search the room. Enter 7 7 6 for the safe, and the mission is complete.