Dude, thats a tough one. There is a way to do it that doesn't require actually using TLW, but just having it equipped. If you don't finish matches with a 2.0 k/d, you will actually lose progress in that part of the quest. I struggled with it for a while because i thought you actually had to kill with TLW. I'd go 1.3 or 1.6 and make no progress. So i went into Mayhem rumble with hunter. Surrounded a lock down point in tripmines. Ready shotgun. When my GG super was ready, i'd run out, get 2 kills, then run back to lockdown point, apply more tripmines to doorways... repeat. What would have taken me months to do, i finished in about 10 games in Mayhem rumble. And hey, look at that! Mayhem rumble is available this week! That way you can maybe wait 2 more seconds to pop the heavy in IB. 5 seconds is fair. ;)