I've been working on the campign on legendary on reach and am on the last mission "not counting lone wolf" and am at the part with the giant mini gun that you shoot down the phatoms with. I got a checkpoint right by the turret so, but, theres still and elite down below that comes out every time i get in the turret and shoots me, so i have to go down there and kill him and by the time im back up theres 5 phatoms there who own me with the guns. I've been trying for 3 hours and this is litterally impossible. i've tried EVERYTHING but nothing works. this part is impossible!