I got this idea when using the Hunter Ring at a shrine, and as the monsters appeared, I thought I saw one break away from the group and run away from the fight area. While I knew that didn’t actually happen, I did think “What if?”
What if occasionally one did try to escape? Maybe a bonus for killing him in a certain amount of seconds, or steps/distance.
Then this adds in extra strategy on how to play it… Do I clear the area before releasing the horde? I usually do anyway if I can (this could also be a feature of hordes released for killing a certain amount of monsters in the lower class). Do I concentrate on the ones staying put, or do I go after the fleeing monster for the reward? (if chasing the fleeing one, the others would probably follow you as well, causing you to possibly fight them all anyway, as well as any monsters in the area the fleeting monster heads.)
Just an idea that came into mind while enjoying this awesome game