Go down the stairs and over to the wine rack on the left. Kick the wine rack and it will open up. Behind the wine rack is a door. Kick this open as well.
The door won't open, so Marcus orders Jack to rip it open. While Jack is opening the door. Locust will attack from behind. Protect Jack.
Once the Locust are dead and Jack opens the door, go through the door. A cut scene will begin. Go back up the stairs. Two wretches will come at you. Kill the Locust.
When the way is clear go back around the wall by using either path. When they join back up on the other side, some more Locust will attack. Kill them. Go through the door. Climb the stairs.
Climb the stairs all the way to the top. Turn left at the top of the stairs. Go through the door thatís ahead of you. Turn right in the hallway. When you reach the room with bookshelves,
Nine wretches attack.
When the wretches are dead a Locust with a Lancer will show up. Kill the Locust.
Go through the door back in to the hallway. Follow the hallway to the left. When you reach the room at the end of the hallway, turn right and head out the door.
Then turn left and follow this hallway to the left and around the corner to the left. Go through the door to the right and up the stairs.
At the top of the stairs on the left hand side will be Baird and Cole. Walk up to them for a cut scene. After the scene start shooting Locust.
This is kind of like end of act 2. Just stronger Locust. Start by shooting Locust from the window up stairs. When the Theron Guard runs for the door, run downstairs and stand to left of door.
Just aim your gun at center and low half of door.
When you see a Locust run through the fire, aim and shoot. Keep repeating this until you get the new orders. When Marcus gets the new orders a Locust will bust out a door next to the stairs.
Kill the Locust. Enter the hallway thatís behind the door the Locust came out of.
Follow this hallway straight then to the left at the corner. Go straight and then through the door to the right. Go up to the door at the back of room. Look right and go up the stairs.
At the top of stairs head straight down the hallway to the door. Kick the door open. Enter the room through the door. Go to the left. Look out the left window.
There is an emergence hole. Close it with a grenade or just shoot the Locust that come out. When the Locust are gone, you can see the door from downstairs. A board is blocking the door from opening. Shoot the board.
Once the door is freed from obstructions, head back to the door. Kick the door open. Exit the room through the door.
Go forward through this little courtyard. In the room there are two exits, take either one and prepare to make a run for it.
Just run through this open area. Avoid all the Locust gun fire. You have 30 seconds to get through this area.
Once through this area a cut scene will begin. This will bring Marcus to the end of Act 4.