Part 11

You'll start by walking into the next room. Your objective here is to find the sabotaged part, which is guarded by a bunch of Orks and some gunners. Use whatever you've got to clear them out. Once they're dealt with, Captain Titus will push the exposed conduit in.

After that, head up the flight of stairs located behind the conduit. Once you're up, go left and interact with the control panel. This is it – you'll fire the weapon and, theoretically, destroy all the Orks on the planet.

Well, that's the plan anyway. It turns out the Psychic Scourge wasn't meant to destroy Orks. Its real purpose was to open a portal to the chaos dimension. After it fires, a new character shows up, and with him come chaos demons. He looks suspiciously like an Ultramarine, doesn't he?

After all the cutscenes, you'll need to head back down to the lift you used to get here. Get ready, because you'll face some demons. These chaos demons are Nemeroth's agents and are a bit tougher than standard Orks, though they deal less damage than Ork Boyz. Your normal attacks or full combos should handle them just fine.

Move into the next area. You'll notice the Orks and demons aren't exactly friendly with each other, but they're definitely not friendly with you either. So, just fight your way through. If you still have the Thunder Hammer, it'll make things a lot easier.

Keep pushing through the next area via the door. You'll encounter more demons and Orks. You need to defeat everything in this section to progress.

Once everything is clear, head to the far left of the room where you'll find a control panel. Use it to open the main gate.

Exit the facility.