"Fine," she grinds out. "If you're going to be stubborn about this."

She honestly isn't sure if he's being stubborn or irrational. Her response to both is the same. Namely, to turn back around and stalk back to the shelter of the gas station rather than the car.

Fortunately, she hadn't added the roll of gauze to the supplies she'd dumped in his lap, so as she sits down, Irene continues rewinding the gauze around her arm, pointedly ignoring him.