And when he starts talking to the president:
You don't have oil industry divers looking around the seafloor and thinking, "yeah, this is where I want to raise my kids someday". And yet, Mars is a planet-sized perchlorate superfund site, and the Moon is worse. So might it have gone the other way?
One argument for pushing rapidly to human settlement is we're in a window now where it both seems at the edge of technological plausibility, and it has some popular appeal. And it's possible to imagine the latter going the way of ocean settlement.
Under sea on the other hand assuming undersea gardens could protect from a dinosaur killing asteroid, with a small population able to repopulate earth in a few years.
PS: the background of the SOMA storyline.
You better check under the sea
Cause that is where you'll find me
Sealab, Underneath the water
Sealab, At the bottom of the sea