It seems like actually, yeah, that's exactly what the wall is for. That's why she needs as many people as she can to learn this dance. Maybe even if they don't have the strongest dancers, the effort put forth by the whole heart of the island could do something about all this.

So, she asks: will Mira, Ogata, and Papyrus learn the dance?

If they can learn it, she'll allow them to help her teach it to the rest of the islanders.