Just move up and fall down into the orange light.
Enjoy the scene until you get out, and when in control either find out what the buttons do or look it up, like in the options menu. Go up and open the doors on the right, then hop over the rail and take the next door to be introduced to your flashlight. Move into the lobby and hear the scene out. After they are done hop over the desk and grab the intel on the file cabinet, and you can press the switch on the monitor to see a tiny scene of what happened. Hop back
over and get into the elevator.
*NOTE: You hold the weapon select button to pick what you want, or tab it to quickly switch guns. You also tab the aim button to do a quick lock onto a nearby enemy.*
When it stops you will be in your first fight. Crouch and waste the guy in front, the one further back, and then the one to the right from the door. Note that they use cover and will flip over light objects to make cover. Collect their ammo and move into the next area to fight more. A few up high and some more down low, and out here you can test out the flip cover by pressing the button shown when near a table. Around and on some boxes is a health pack, and in the corner by Stokes is another intel.
Go through the door she opens and nearby is another intel. Move along and by in the window-ed hall you need to sprint to avoid the chopper fire. Pick up the vest and ammo, then go through the door, listen to the chat, and then pick up another intel. Go through the door, hop over the wall, and pick up the med kit, something you can use whenever. Like through the next door in this big fire fight, but make sure you pick up those frags. Use them when the enemies are hiding behind cover. There are about eight or so of them, but not many more than two at a time. Collect the ammo and go out the doors they came in to learn of the adjustable fire rate of your guns.
*NOTE: To adjust fire rate on the PS3 I hold L1, select the SMG with the RS, and then move the RS over to change the amount of bullets a trigger press will shoot.*
*NOTE: You can either pick up the items you find or move over them, whichever works best for you.*
Go out the door and kill the two soldiers as they drop, then the two that come from the right side - you're not alone if you see some guns fly into the air. Ammo, grab the armor behind the bar, and then duck under the gate to the left in the back to get out. There is another fight with another group of four dudes in the kitchen. Pick up the med kit, move on, pick up another, and then kill the lone enemy on the roof.
*NOTE: It's important to be smart with your ammo. If you pass a gun because you're full and then do a battle nearby, come back and get that ammo before you move on, that way you get the ammo furthest back and leave the more forward ammo open to picking up if you get into another fight or something. Not a big deal, just something to think about.*
Hop out and jump to the scaffolding and while I don't think it will fall you may still want to jump to the other side quickly. Duck into the vent and crawl to the other side, a dark area. And when it's this dark and your flashlight flickers you know stuff is weirding out on you. Walk around the pool, to the other side, then hop in the water.
Hope the little scare got you! Nice and sunny isn't it? You can even see the city profile on the balcony. Take the door out, pick up the armor in the towl room, use the door nearby to look back over the pool, and then turn around to pick up the nice little ammo and health... now that was a good one.
Take the door by the sinks to get out and soon you come to the next fight in the penthouse. You may want to toss frag at the two enemies in the back, then kill the rest who are all around. Pick up the intel on the counter top, and there is nothing else in here so go up the stairs, kill the enemy that pops out of the door, and go through it. And when the hallway is this long you know something is going to happen. Around the corner use the box and go inside - the bathroom door on the side of this bedroom has nothing. Pick up the two intels and check the marker board to see if those faces look familiar to you (it's your team). Go down the steps for a scene.
Turn around and basically return to the piano in the penthouse.