The setup is worse:
Omni was turtling behind one of the podiums there way in the back so I had the "brilliant" idea of jumping up on the platform near entrance to lure her out for my teammates. Take two sniper potshots and she's summons her wizard friends AND a poison cloud right on top of me. Cut to me trying and failing to make it back to the entrance room alive. So my teammates are focused on the left doorway at the entrance to try to kill enough ads to at least get a bubble revive. I watch in horror from my death cam as a single thrall is thundering around the corner of the right doorway and by the time I yelled "right side heads up" he was already midair for the Nightfall ending blow.
As far as fails go, it was a pretty memorable series of unfortunate events.