[The effort she put into moving finally does something, just not in the way she had intended before he released the binding himself-- and to say that she's a little put out by that is a gross understatement. Did he think that she couldn't take any hit he got in before she regained control of herself? He had an advantage, he should have pressed it. Holding back is insulting.
She means to show him that now, as the strength that was thrown into immobile limbs is suddenly freed up all at once to propel forward with impressive force behind her. Watching oneself in a casual match isn't the same as holding back, her swings could still break ordinary men. But now, her blade is raised, and coming down to meet his in a blow like from a giant's hammer all the fraction of a second before he's upon her, the ring clear and incomparable to the previous ones, and she doesn't hesitate before tearing her sword away from his and bringing it down the same way again, relentlessly]