There are times when sleep truly is the lesser evil, so lesser that it loops back around into being a good thing. This is one of these times.

Or, it would be, if she was nodding for the reason he hopes.

Papyrus focuses hard on that hope, too hard to notice the signs she means something else. And while he notices the odd echo... he assumes it's just the result of a large building they're passing by. "For the best! A rejuvenating nap, so now you're ready to walk yourself to safety. Relative safety. I heard the doctor's set up camp in a big building, so that's where we're going."