They didn't pursue him because it was a set up. They weren't chasing him so much as herding him because they knew where he was going and Kunzite was meant to overpower him. As for Kunzite not being under complete control, I always assume that he was the last one to fall, and he is also the strongest of them.

The whole point of Endymion striking him was so that it would look like he escaped. Although Kunzite made it seem like Endymion was doing him a favour, in reality he's the one doing the favour. He's protecting Endymion for the last time. Do you think injuring Kunzite like that was easy for Endymion? It wasn't.