She wants to ask if he's sure, because he really does seem like he needs a medic, and at this point the Organic Mechanic is actually too frightened of the Wives (a revelation, imagining anyne would actually be afraid of them!) to not do as he is bid - Nux is going to get the best care. But she doesn't, trusting him to know is own mind.

Instead she keeps hold of his hand, an begins to guide him deeper into the Citadel. It's just as much up as it is in, and the stairs cut out of rock that she's guiding him to lead to the very top of the Citadel, an heretofor forbidden zone full of lush greenery. Her fingers tighten around his. She's taking him to a sacred place.