Cross the yard and enter the next part of the school through the red doors.
A group of soldiers will come down the corridor.
A heavily armored soldier will be waiting outside.
Once you kill him, you can get his Hammerhead nail gun.
Near the basketball court you will find a locked way to a basement. Shoot the lock and go inside there.
Once you enter your objective will be to locate the nurse's office.
Pass through the guarded library.
The soldiers will seal off some of the exits.
Go towards the end of the corridor.
Enter the last door of the restroom.
You will find a hole to pass to the other side of the building.
Find the staircase to go up.
Alma will visit you.
You will end up on a rooftop. Prepare for a big fight here.
The replica soldiers will drop down from a chopper. You can shoot them while they slide down their ropes.
Enter the service entrance and go around the next building.
Jump over the railing and walk across the vent duct.
The vent will lead you to a window where you can jump in.
The two enemy factions will have a firefight here. Surprise them from behind.
Pass the cafeteria.
Go through the kitchen and expect a few more soldiers.
Enter the cold storage compartment.
You will find a place to drop down.
The basement will be haunted. The ghosts will try to attack you if you go too close. Shoot them a few times to stop them.
At the end, your path will be cut by a gas leak.
The valve is near the place you have to cross.
Shoot the padlock to open a gate.
You can kick over the burning desk to pass.
Pass the room with dirty windows.
Some soldiers will be guarding the elevator.
Use the elevator to go up.
Deal with the soldiers in this place and go straight forward.
Follow the sign to reah the offices.
The nurse's office will be on the right. But a keycard is needed to open the door.
Go through the offices in the opposite direction.
Take the elevator up to find the principal's office.
At the end of the corridor you will find the principal's office.
The keycard you need is just outside the principal's office. But the principal himself is not happy that you took it. Time to fight him.
Just like the controllers in previous levels, the principal will run around and try to command dead bodies. Kill him as fast as possible.
Get back to the elevator to go down.
Fight off Alma.
Jump down the elevator shaft to reach the lower floor.
Get back to the nurse's office door to use the keycard and enter.
Go behind the backdrops of this observation room.
You will notice that they were recording this room. Go through the exit door.
Fight your way through there to find the nurse's office.
Use the keycard once more.
When you finally find the nurse's office go near the computer desk and press E.