Chirada or suparna for the off tank or main tank and i see no difference !

Why sometime i take the big attack, and sometime i don't what can prevent it ? I realy can't figure it.

In each phase i have take 2 super attack (one for garuda, and one from chirada or suparna, nothing change at all the first we kill). and another one attack, what that mean ?

Less of dps ? We was good i think, we have try burn chirada like we allway do, and i still take the super attack, we have try with suparna first and no change at all.

Evade this attack is so random, sometime i run far away and i get hit, sometime don't, running for evade it is more dangerous i think, because i go behind the pillar who can't cancel the cast of the healer. I realy have hard time beat her, sometime that work well, sometime that work very bad. 4 Big attack in one phase is so much btw, i can't use so many cd in each phase.