The tunnel seemingly goes on forever. As they pass one gaslight, they can see the dim glow of the next in the distance. Fiona's not sure how long they keep walking, quickly losing track of even the number of lamp posts.
After a time, the tunnel begins to get taller, until the ceiling is beyond view, even when they're directly under a lamp.
“Curious,” she says, almost to herself, but the cats have already left her. They continue on for a long while, one lamp to another, when she starts to feel a cool, gentle breeze. Looking up now, she can see a thin band of stars. They are no longer in a tunnel.