I can't believe I got it. I had to check Bungie stat tracking previous games, it took me over 12 attempts to finish Heist Battleground Mars. Over a week doing it and I finally got it. Just had a great couple of a guys helping me, every little bit helps, even as I'm typing while being chased by a boss. Fingers tend to slip. And any time I dropped a well, the thought came to me, "this will give orbs for my fire team." But if your curious, I just planted my seat on the ledge and just spammed Wish Ender shots on the boss, so he would sit still, He would turn his head to see the fire team, but like a tap on the shoulder he would stay by me. It's not a cheese because I did hop off to res a guy and then had to get back and get to continue to keep focus on me. It's just my part in the chaos that this is Grandmaster Nightfall. If I can do it, you can do it.