Frisk isn't eager to bring that up either, and the subject drifts away into the breeze without a fight from either party.

"Uh-huh! Ev'ryone from th' Underground made it out!" Even Flowey, though Frisk isn't sure if they want to make the trek back to the apartment for that reunion. And Flowey would catch on to the oddities very quickly. ...Sans would too, obviously, but hopefully Papyrus will understand how THAT could be an awkward kettle of fish to stir up.