Honestly, a leg is not ideal, and this is part of the reason. She grunts at the impact, and she does, briefly, lose her grip, but she's closer now, and that gives her the option to grab in a way that's better for her and worse for him.

She will hurt later. She will hurt a lot later. Right now, there's only adrenaline.

Ylva lunges forward to grab the back of Siffleur's neck in her jaws, to hold and, if necessary, to bite down with all the force she has.