Usually, by the time they are fleeing, it wont make much difference. the only time I saw it happen is with the spartans. When you can use it right behind the unit as they are fighting or if you are fighting next to them. If you use it then, they will be less likely to flee and have more resolve for the rest of the fight. I don't know about the radius, but if you have the camera restricted, it is probably as far as the camera can go.