Kitava act 5 bug

I just discovered that you can break the Act 5 Kitava fight by using Dash...

So basically at the last moment, when Kitava was about to destroy the Staff of Purity, I dashed... The character is still alive, kitava is just standing there, and Sin is nowhere to be seen.

Not sure exactly what to do... Really hope I don't have to start leveling another character.

do u get the solution..i also stuck in act 5 kill kitava