It was pointed out by Fiamma that even when forcibly taking the power of the Archangel your aligned with, it’s extremely dangerous for any God’s Right Seat member to do so just because their adding a shit ton of power already. Acqua on his own runs on constant 200% overlocking with both Saint Powers and God’s Right Seat powers with his Divine Mother’s Mercy ability keeping both in check. Without DMM, he would literally explode from his two powers otherwise, so adding even more power than that was already too much him. He took more than half its power before expiring and nearly crippled it too. That and Gabriel that Fiamma called might have been stronger compared to the clumsily summoned Angel Fall Gabriel that Kanzaki compares Acqua too,