For all that she's gotten mostly used to the idea that it's hers now, for reasons that she can't quite say she quite understands, Aqua still isn't terribly used to the feeling of a tiara. She's managed to figure out how to keep it from actually falling off, fortunately, but it's still not something she'd ever thought she'd be wearing into battle.

But now is not the time to think about that. Right now there is enemy to fight, and while she hasn't missed the similarities between the Nightmare they're fighting and Luna herself, it's not enough to keep her from the tasks at hand. Namely, taking care of Nightmare that stood before them, and that was something she knew how to manage, as she brought up her own shield just long enough to block the incoming blast of magic before retaliating with one of her own.

In this case, a set of three fireballs all in quick succession. There was certainly no reason to hold back here, of all places.