What happens on the morning bus when the narrator notices a bit of rice on the Woman in the Purple Skirt's jacket?

The narrator tries to flick the rice away, but the bus swerves and she tweaks the Woman's nose instead. The Woman lets out a yell. The narrator assumes it is regarding her touching her nose, but the Woman says someone groped her. The bus driver pulls over and the accused man is removed from the bus and taken to the police station.