We know Momo wants to open Wano's borders (=destroy those stone walls), but he didn't want to do it right after Kaido's defeat
So my headcanon is this:
>BM and Kaido are stuck in lava but alive and still floating around in the waters below Wano
>1056 will be setting up the Straw Hats+Yamato to leave Wano and say their final goodbyes, but the last page is a big earthquake out of nowhere
>What's going on? Well, out of instinct, Kaido and BM who are both trapped in the lava below where Pluton is, stuggle once more to break free (the volcano eruption like 10 chapters ago, that Momo imagined was a sign of Kaido's defeat, was in fact the exact opposite, and back then as you can see in the image, there were cracks already that reached the outer Wano walls)
>1056 ends on the aforementioned big earthquake cliffhanger
>Cut to 1057, we see the walls crumble and everyone panicking, the SHs on the surface who as I said were about to leave get informed by Robin and Law what breaking the walls means, and later in the chapter, Zunesha arrives because he also was confused about what's happened, since he assumed it was his task eventually to break them
>1057 ends with Pluton "awakening", which 1.) Pluton might be a sentient being, a ship that has eaten a devil fruit (like Funkfreed), and thus below the sea, it could not escape all the water on its own and 2.) Pluton being awoken is a good thing and will be helpful to either the SHs (similar to Shirahoshi), or for Wano's self-defense, or both; since Oden implied Wano needs to open up, and he saw the true history on Laugh Tale.
And with that...Schizo Headcanon...おわり