Gotta stay together and have shotguns with all three people. You rotate as valus rotates. There is cover for the rockets on all sides of the map. If you guys use scout rifles and rockets to hurt valus and your shotguns to mess up anyone that comes your way you'll be good. Just have to get a feel for where to group up at and where to go when valus moves. If you play it on normal first you can get used to the strike. If you stay as far away from him as you can as he moves you can use the cover to stay out of harms way. Those metal sheets that come up on each end of the room are good cover from the rockets. I recommend void shotguns as they will one shot the purple dudes. My set up was fang, swordbreaker, gally. I used abyss, icebreaker, hunger for everything up until valus. Hope this helps.