Completed and the team I was part of had a different strategy to taking out the boss. I as the Defender lead the boss back up the stairs and tanked him, jumped on the tallest pillar and kept all focus on me. I also had to make sure that I orientated the boss so that a sniper with one hell of an exotic cannon could get constant crit shots on the boss. He was in a position the harpies couldn't get to him and with nothing shooting or disturbing him, just kept critting away.