Thanks to the physics of cartoons, where things that are off-panel can’t be seen by anyone on-panel, running for the panel borders is actually the smartest move.
You would think with ships and other things randomly floating out of the sky, at least one or two large ships would have ended up floating in the ocean nearby, and largely intact.
They’re on a beach. All hell is breaking loose above them. Unless somebody has a boat concealed about their person, the only way to go is start walking down the beach. This has the advantage in our world of eventually leading to some form of civilization. Of course, sometimes you walk for a few days and discover your own footprints. This is how you find out you’re on an island.
Hard to tell if those are explosions or just distant landscape.