"Must be! But I'm the monster ambassador to all the humans! ...or I was." Their expression falls a bit, and Frisk frowns at the floor. "I hope we can all get home soon. I gotta take care of everybody, and Mom's gonna be super worried."

Frisk was kind of hoping Sans might show up through one of his shortcuts, but he doesn't have any way of knowing just where Frisk is, now.