It likely that SH still not leave yet and chapter end with Yamato ask luffy to join.
Or with Yamato trying to catch up with the SHs then stopping on the castle roof (the order is not clear).
And finally, the last panel of the chapter may be the SHs leaving and the editor's note on that panel "A new adventure begins" or "Will Yamato join?", which depends if we see Yamato on the sunny or not. Just purely speculating.