How to complete The Worm Churns?

[Searry]

I destroyed the stifler in the chasm. Went to the arena. Then sabotaged the anatomical opera after the guy got mad. Then went back to the pit like it's described in all of the guides but I cannot progress in this quest for some reason and I don't know why. When I go back to the pit there is no fight. For example in one guide it's described like this:
"Sacrifice to the Warp Gods
The next stage of the quest will require players to visit the Pit. If you’ve not already been back to the Pit since the first Arena, you will have a scrap ahead of you. No matter if you sided with Malice or with the Commissar, you will need to go back to the pit. While in the pit, you have an opportunity to take over the Pit and become its leader. Once you’re the leader of the Pit, then you can sacrifice the Shriekers that side with you as a final act. You’ll need them to swear loyalty to you as part of the heretical option to be willing to sacrifice them."

What is going on? Do I need to reload a save from the moment I win the second arena fight?

[Searry]

Ok. Really weird. I killed malice and then sacrificed to the gods and now I am supposed to go the arena and destroy the last stifler.