It's the minotaur bad end scene and here's what you need to do to unlock it.
1. After investigating the site where Groknak was kidnapped, don't ask Jadk about the bottle. When you go to the merchants, you'll find a letter. (It makes no sense at all why the letter disappears if you ask for Jadk's help, but that's how the game is coded.)
2. Now, go to the bandit camp without waiting for Neve. If you don't have the letter or Neve with you, you'll immediately be caught and get the scene with the human bandits. Since you have the letter, you can make some progress into the camp.
3. When prompted, kill the guards. Choosing "distract the guards" will just get you the human bandits scene again.
4. Enjoy.