In this chapter, Titus is finally able to get rid of that power unit he's been carrying around forever, but what else can go wrong? Quite a lot apparently.
Keep moving forward. Titus will have a short conversation with Drogan about his servo-turret defenses. Open the door in front of you. Shoot down the servo turret, grab some ammo and weapons, and approach the next door.
Shoot down all three turrets and Titus will make a note that they have to kill even more turrets, or else shut them down. Drogan says he can shut down the turrets from the central security room, so there's your next location.
Run forward and destroy turrets. Pretty simple stuff.
Kill another turret. Move forward and head right to pick up a Servo Skull (Transmechanic Petronius 1/5) then head towards the objective marker again.
Go through the door, murder more turrets. Open a door on your right to activate an exit. Follow the objective marker to get to the exit, and open two doors.
A Support Pod should be right in front of you. Run up to it and get the Kraken Bolter, an upgrade to your standard Bolter. The heavy gate on your left will slowly open to reveal the firing core, but you can't go through it. Instead, go through the door on your left once the switch turns green. Then open another door.
Use your Kraken Bolter on the hostile turrets then proceed forward, through another door.
Move forward and then left, taking out more turrets. Open the door at the end, then follow the objective marker to still another door, then a third door.
Destroy the turrets guarding the command room door, and then open said door, grabbing some ammo. Pick up the Purity Seal from the Support Pod on the left to unlock Supreme Fury, which upgrades the amount of Fury you receive from kills. When Drogan opens the door in front of you, you should get a new objective: Prepare Firing Sequence.
With the security disabled, Orks start swarming into the facility. With strategic use of Supreme Fury, those Orks should be obliterated in no time. Once everyone is dead, Drogan instructs you to place the canister inside the power core. Once you do so, you're not quite out of the woods yet! Drogan needs you to manually restart the array alignment, so do so. Follow the objective marker to the nearest door and take the lift inside. After a short conversation, the chapter will end.