@AuraQuartz, I’d say it’s just more of her constitution. Hades said that if her mana was “normal” it wouldn’t hurt that much. Put together with the fact that her body has barely had mana flowing in her due to the suppressants, her body is not used to the flow, much less a potentially absurd amount.
It’s like filling a balloon with water, if you turn the tap to full power at the start, the balloon would most likely burst very quickly, but if you do it slowly or put in moderate amounts, it can handle the pressure