So basically you are only continuing to play the game because Alma loves to just mess with people. To the right of the locked front doors is a padlock to open a path to drop down. Crawl into the classroom and pick up the intel in front of the desk. Lift the bookcase in front of the door and go into the hallway.
In a room on the left is a nice video to confirm that we all indeed need to visit the nurse's office. Continue along the path and up the stairs. In the first room is an intel, and if you continue down the hall to the dark dead end you can pick up stuff and get a few cheap scares. Come back and go through that classroom with the intel and tip-toe over the beam to another room. Slowly go out and right, drop down, and into another room where going out the door leads to a not so good result; just move up.
You appear in a new room. Move along until you run into a man playing the the piano. Yes, this is another puppet master. Hopefully you don't get stuck like I did and have to waste all my med kits. Just run around again, use your reflex, blast him, and shoot down his puppets; there isn't much ammo in here, but there is an armor and med kit on the sides. After you take him out, lift the case in the corner. Push aside some cover and crawl under to enter the hallway from hell.
I don't think the ghosts here will harm you, just freak you out of your mind. Get to the end at in the room on the right is a reflex injector under the projector, which you can slide over. Now go out and you will enter into what I consider the most F-ed up horror sequence in any FEAR game, probably any game. You lose your flashlight, the ghosts pop up for surprise attacks, and you can only see when the flickering lights flicker. It's seriously messed up, and is enough to jusitfy this games claim to horror. The only advice I can give is to shoot the ghosts when they are near, and go around the room and jump out the window, but of course I can do nothing about the horror. There are some supplies you can get once the thing is over, but going down the next hall will have one more encounter with her, so just mash melee to shake her off. At least after that horror sequence you can say "Hey dude, I'm totally being scoped out by some naked chick."
Moving on, you get the feeling that she's doing screwing with your mind and now the soldiers are about to attack. Get your ASP ready and go out to fight about eight Replicas; it may be better to snipe them too if you have ammo. Kill them and head through the door for one more enemy and some armor. Approach the rubble to get your next objective to turn off the gas flow. You need to
return to the yard.
I really hope you still have your missile launcher and some shock grenades. Just go out and shock the armor suit, and shoot it with a missile twice to blow it up. If you don't have missiles I think the ramp to get up will still be there, so I guess you can just shock the suit and run up the ramp.
*NOTE: If you did not bring missiles to kill the mech suit, I assume you must just continue on with him firing on you. I guess instead of treating the fights like fights you just use the shotgun to wildly run by them and into cover.*
In the second room is an intel, and I would guess the hangman on the chalk board is eraser; oh sorry, that may have been a spoiler. Go down the hall and there are steps that lead down to a med pack. Go across the roofing and there will be five enemies in the room, four that will be inside the room and one that emerges from the door when you get in, so toss in fire or mines. Pick up the armor and continue along the roofing to kill four enemies that drop from above, and then one more at the end.
Get in and turn off the gas by using the red valve on the right. Drop down, pick up the grenades behind you if you need them. Then go over the rubble and go left, but you don't need the med pack because maybe the chopper blades hurt, I'm not sure. Anyway, in the corner is a hole in the wall, so go up and drop down to meet your team. You have to envy their innocence, but not the fact that they are sure to all die. Mash melee to end the level.
*NOTE: No more mechs to fight while on foot, so feel free to use the missile launcher as you see fit. Either save it for like the second-to-last level or use it now and carry a shotgun throughout.*