The longer it remained power, the more it draw from the Mana of the Witches that created it. That included those who were fighting the 3 S-rankers and those that powered it from outside the Magic Circle.
At the same time, the longer the S-rankers spent inside the Magic Circle, more flaws would be revealed to them, allowing them to break free, thus stopping any chances of the Witches to ascend.
'We need to end this, once and for all.' Her eyes wandered around, searching for anything she could use to kill the S-ranker trapped with her group.
Rummaging through her pack once more, she found herself with the sole combat potion she ever knew; explosion potion. Oh, there are more combat potions but the one she spent the most time creating is the explosion potion.
