Congrats :-) I thought it was impossible after our rumble the other day but I managed to do it on my own this afternoon- I was determined to do it cos I've got two exotic bounties that required it. I finally twigged onto dealing double damage by using the damage type that correspondes to the enemies shield colours, and it helped ALOT! (Can't believe I hadn't picked up on that earlier!). That and a couple of good 'draw out and pick off' spots ;-)