We know that the Act can't end without Hiyori playing her shamisen. So, there has to be a reason for Oda to cut to Hiyori.
For me, it can be accomplished in two ways:
- Hiyori is already captured by Orochi and taken to Onigashima. Momonusuke will be taken to the cell where Hiyori is being held and then she will play the shamisen.
- Hiyori will remain in Ringo. But Kanjuro will head towards Ringo with perhaps a flying six. So will Zoro. Last scene is Hiyori playing shamisen in Ringo.