She did not sign up to be a burglar. Lines, duck dodging, and constantly contorting into a different shape to slip past these things are annoying. Balancing where any and all of the spikes are coming from in every direction. Sticking to wherever there's enough space to get both feet and precarious shifting balance from one foot to the other foot around clusters of spikes where she can't.

If they weren't razor, she'd consider some gymnastic climbing of them, but Geralt gives a grunt up there, and that's just her point, isn't it? He's shaking a hand dripping blood, and Jo only calls out, "Are the walls actually getting closer? Are you going to fit up there?"

What. It's a sensible question. If the walls kept moving in up there, and Geralt can't, she's moving in the wrong direction. Though she's already well into the idea, there is not a right direction anywhere in this place.