S-4 is always happy to see one of his friends out and about, and had just been about to give them a cheerful welcome when... they tripped? That's not something Frisk usually does. Maybe they're not feeling well?

Whatever may be happening, S-4 can't help but yell out as Frisk falls into the fountain, rushing to their side to pull them out of the water.

"Frisk? Are you okay? You have to be more careful!"