Maddie’s female friends, at least, admire Maddie’s ability to fix engines—Beryl doesn’t seem to see anything wrong or odd with Maddie knowing how to do this. But Maddie seems aware that Beryl might be an anomaly—or, even if people will generally be okay with Maddie knowing how to fix engines, this is no guarantee that anyone will
pay her to fix engines. Jumping back into the frame story like this shows that the narrator is writing under scary, horrifying conditions—and perhaps suggests that her writing is an escape from those conditions.