Search for info regarding the Locust's stronghold. Enter through the demolished door and to the room on the right. There lies the Interoffice Memo.
In the next room you will see a group of Wretches through the glass. Don't go inside but backtrack to the control room you went next to just a while ago. Turn on the alarm and turn it off after getting rid of all the creatures. Now continue forward.
In the room with the grated window you will find the Memo: Dr Doug Sato.
The security system won't react unless you touch the beam of light. At the first sensor, roll to the neighbouring room and shut it down. You have to remember about shutting down the system every time because otherwise Dom won't be able to follow you.
You will avoid the light beam in the locker-room by moving from one cover to the next one. Also, the beam won't react if you run through it.
In the corridor with three sensors, wait for all of them to turn left and use the switch on the right wall.
The flamethrower will prove useful once again, when you will have to cross a little courtyard. When you will get to the kitchen, wait for some of the Wretches to be killed by the security system. Kill those that manage to get through.
In the operating room, on the right side you will find a short corridor and a door, and inside the New Hope Medical File: Ruth.
Just run through the long corridor with multiple sensors. After a while you will have to split up with Dom.
Steering the Towers
If you decide to steer the turrets approach each swath and press it. When Dom gets through, activate the next one. In the end press the switch opening the bulkhead.
Stand before the beam and wait for Dom to deactivate it. Then quickly cross it and stand before the next one. At the end of the corridor, press the switch opening the bulkhead.
Go into the room with the containers and wait for Jack to open the passageway.
Inside press the switch. Something will come to life in the containers.