Sephiroth probably would have ignored the rescue efforts if he wasn't already in the city when people started showing up. He might go along... Depending on whether the group that gathers looks competent.

He seems indifferent to the preparations while he stands near the Pokémon center waiting. His Pokémon are quite a bit more interested though only two of them are outside their Poké balls. Minerva keeps jumping from his shoulder to the roof of the center and then back again while Fair is lurking nearby watching people.