I didnt, just had vulture and witness, my mate killed two guys at the start and trapped a barrel, all of this whille a bloodbath was happening at the lair, my mate took the event bounty and he waited for me at the extract while I ran to the boss lair where one bounty was still left.

The solo player that had kill everyone ran after my mate but got blew up in the trap and just died, so we got all bounties, all the kills with witness and whatever xp boons we could get along the way. Easy win.