Get out of the car and enter the building. First explore the area as Aiden; you can find a [BLUE ORB] in the room to the initial upper right; look for the (white) dot.
As Jodie, head towards the elevator and take control of Aiden. Go down the shaft and move the object blocking the door. As Jodie, channel the body inside (align the orbs so the stream of energy goes from the body to her head), then ride the elevator down. Head through the door and proceed through the hall, then open the door from the other side as Aiden (hit the switch on the desk). Be sure to also channel the body in this room (channelling the bodies is good for a trophy). There's a third body you can channel in the next room. Move the servers out of the way to reach a ventilation duct; head through.
In the next room, channel the body of the scientist in the middle of the area, then bust a table through the glass walls on the left to continue. There are two more bodies to be channeled in this hall. After this, move through the flames as Aiden and hit the fire extinguisher so Jodie can put out the flames in front of her. Proceed through the glass window on the left and approach the scientist.
Prepare for a fairly lengthy fight! Again, move Jodie in the direction she's already moving her body in; you're reinforcing her movements. When he's taken care of, go to the other scientist in the room to also channel .. oh. Anyway, continue through the destroyed hall and channel the dead soldier there before moving through the nearby doors (have Aiden help Jodie get through). In the room beyond, prepare for another interactive scene in which you'll have to move Jodie in the right directions. It's fairly short, fortunately.
In the icy hallway, make your way to the other end. Great.. you need a keycard and it's on a body at the far end inside the nearby room. It's always the last body, isn't it? Another interactive scene triggers. After this you'll have to take out the dead scientists one by one with Aiden, which is child's play, really. The hall is empty; in the next room, head over to the controls and flick the switch. Go through the door after that and prepare for the final battle of this chapter.
As you climb up the ladder, Jodie is attacked by the entities. It's important to know how to deal with the entities, and there are two different scenarios. In the first scenario an entity is holding on to Jodie. These are destroyed by holding both analog sticks towards each other (all while holding R1, of course). The other scenario concerns entities flying around or entities very close to Aiden. These are destroyed by pulling the sticks down and releasing them; they can thus be defeated very quickly.
Proceed over the catwalk, avoid the incoming entity attack - otherwise fight them off - and climb the ladder. Proceed over the catwalk and over the railing, where you'll have to fight off more entities. Another fight ensues on the crane; keep pushing onward after this and leap over the two gaps at the end of the catwalk to end the chapter.