Vaal Foundry Boss Fight Cut-scene Death Issue

So,

Long story short. A party member started firing into the pit (merc) before I had used the elevator to enter the arena. Not sure exactly what happened next but people managed to get into the pit and start the boss B4 i took the elevator so by the time I got into the the pit (mind you I am animation locked) it dumps me in the lava for insta death.

Ya might want to look into this one