[Stone clings to the prow of the boat tightly. He's actually seen something like this before, and so is only surprised rather than particularly afraid. At least it's not a whirlpool version of the underwater passageway the groundlings' boat took, last time.]

I think it's a tunnel that will take us somewhere else. Not drown us. But if there's a problem, I shift big and carry you both back to the surface.

[He does wish he had claws right now, though. And the strength he's used to. Clinging with old-man fingers is actually kind of hurting said fingers.]

Might want to hold your breath just in case, though.