[She's more offended than surprised that he would still stop her when she'd made it clear she was done. He wants to give excuses, explain more, appeal to her? To hell with any of that.
The ire that had gone to simmering under the surface becomes one last, indignant flare up, but isn't expressed with words-- she has no more for him to begin with-- and instead with her hand striking out swiftly enough to impress even herself, aiming to clip him across the face sharply. A part of her marvels in shock at the extreme action, the rest clinically accepting in her current jaded mood.
There's no satisfaction in it, no repaying him for wronging her; simply, since her previous attempt failed, the clearest message that she's finished here. Her expression is just the same as when she turned away before-- why she did so in the first place, she can't cover it up no matter how she wants to, and she's never wanted to more than now-- and she manages to look at him unwaveringly for nearly half a moment before brushing past him, an added quickness to her step this time, to make sure she leaves this time]