Did I miss something? I was under the impression Susannah's wheelchair was left behind in Lud when they boarded Blaine.

Yet, at the end of Wizard and Glass, there are wheelchair ruts in the ground as if they have wheeled her away from the Green Palace (during the mysterious transport from the interior of the palace to a point thirty miles away and back on the Path of the Beam). The chair is referred to again, and the story picks up in Wolves of the Calla as though it's forgotten that she shouldn't have a chair.

Is this a plot hole, or is there an explanation I've missed (or one coming?).