Invincible marines in Spartan Ops? WTF!?!

I had enough of that -Yoink- dealing with Noble team on Reach. I don’t want AI help that I can’t choose to kill off. When I park my -Yoink- hog and jump in the back top shoot thing sat a distance, I want it to stay there rather than having an AI jump in and drive straight into the enemies to die.