The blanket disappearing under the door is reassuring, a sign that the girl on the other side (and he doesn't know for sure that it's not a grown woman with a young-sounding voice, but his paternal instincts are hard at work now so he thinks of her as a girl) is still well enough out there to move. Her thanks go unremarked-upon; a blanket is the least he can do, and even that may not be enough.

"I'm going to try the windows," he tells her. "I'll bring you more blankets soon if they don't work."