* Indicates it is unusable by player.
Part 1: East Wing Edit
You begin the mission on the rooftop of the East Wing. Walk forward and look find the chimney cowl (the iron/metal object sticking up) and you should see a 'rappel' option appear in the interaction menu. Activate it, then rappel down to the open window below. Head inside and stick to the shadows until a guard enters the room. Once he heads to the bookshelf, knock him out and head towards the door he came in through, avoiding the surveillance camera. Open the door, but avoid exposing yourself inside of the hallway. Peek the camera around the door and you should see two guards: one patrolling and one standing, facing away from you. Wait for the patrolling guard to turn around and move towards the stairwell door to the left. Open the door and immediately cut left, heading down the stairs. (You can go right, going 'up' the stairs in order to perform wall jumps, grabbing onto the metal beams in order for you to reach a small upper platform. There are extra items if you need them, they may help out.) Once you head down the stairs, shooting out or slipping by the cameras, head through the garage door and stick to the shadows, moving through the parking garage area.
The garage Edit
You will notice a vehicle with its headlights on and a man walking past the front of the vehicle, sneak behind him while he is busy and grab him. Interrogate him for information, then knock him out. Now, just backtrack to where you entered the parking garage, but be careful as there is a guard now at the staircase entrance (this is only if you didn't knock him out in the hallway from before). You can either grab a glass bottle (which should be near the elevator shaft), throw it on the ground and sneak by or you can throw the bottle at the guard's head and knock him out. Once he's been taken care of, head back up the stairs and to the first hallway that you entered into at the start of the level. Knock out the guard or distract the single guard waiting in the hallway, if you haven't already, and open the door on the right side of the hallway at the end of the hallway.
Crossing through the kitchen Edit
Be careful here: point the camera up and you will notice a security camera is watching the room. You can either pop the camera with a round from your Five-seveN, or you can simple turn the light off by switching the light switch just next to the door. Head to the other side of the room, and open the door - you should be greeted with a short cutscene of a chef opening window panels. Now, you'll have to climb up and move along the small ledge trim that hugs the wall. Keep moving to the right until you are over the window that the chef opened, and drop through the window.
In the kitchen Edit
The chefs are working on a meal as a guard comes in inquiring of the situation, he will leave and you must attract their attention to noise. Use a bottle and toss it somewhere else so the chefs will investigate. Once you leave the room, lookout the guard that will turn to open the lights. You will enter through a balcony on the main lobby. drop down and you will find a guard checking the computer on the desk. Once you bypass the guard and access the computer which will deactivate the laser grid, a colonel will come downstairs and you must grab him to access the retinal scanner on the back of the ground floor.
The courtyard Edit
Entering the courtyard, you will notice a glass elevator that goes up to the highest floor, Vyacheslav Grinko and Philip Masse will be talking and you must use the laser mic to listen to the conversation. Once you are done, a couple of guards will come out of white doors in the front of the building you must enter. You must go the vines near the walls and climb through a window opening. Call the elevator and hide back as guards will leave once it reaches down. You can hide back against the dark walls or next door in a closet. A disposable lock-pick is available to pickup. You must go up with the elevator up through the offices.
The office Edit
In the office halls there are cameras and guards patrolling back and forth. There is an office just beside the elevator that you must lock pick and enter. The office has a vent shaft exposed so you must jump up and it will take you on the other side of the corridor. The camera in front of you will see you unless you take the lights out and then enter through a close nearby some objects and there is a ladder taking you on the roof.
Rappel down and you will see a guard moving back and forth in Nikoladze's office. You can jump to enter window, smashing through or shoot the glass to gain access. Once you access the computer, an alert will occur which will send soldiers into the office. Make sure the place is dark and you are back against the walls far away the desk or hang bellow the window and the guards will leave. Access the computer and make your way out while a guard is patrolling the hallway.
Go to the left side into an open door and run down the stairs to the back passage of the roof and enter the shaft, hanging on ledge and drop down smoothly, careful cause guards will pursuit you once going down the stairs. Once down into the garage you can run down the place and find the van with Wilkes shooting a guard dead.