> down to the "liquid door" hatch inside: Moon pools or wet porches have been ubiquitous in underwater habitats for many decades. https://en.wikipedia.org/wik

> down to the "liquid door" hatch inside: Moon pools or wet porches have been ubiquitous in underwater habitats for many decades. https://en.wikipedia.org/wiki/Moon_pool https://en.wikipedia.org/wiki/Moon_pool That you know of them through a cartoon is not a good criticism of the proposal.