In that same interview they show some other AI stuff, they have a troop running around a Level, and they put more and more debris around and the Helghast react and avoid each piece.
During some other videos you notice that the AI's dying animations are affected by objects in the world, they will trip and fall over other troops and walls and polls. Plus the fact the one troop starts to run and hide when he has a rocket being pointed at him is great.
But one of the best parts is when Sev hides in an alcove and the Helghast follow him, he then shoots the guy in the face and you see him grab his face as he goes down and starts to bleed.







