There's no pool of inert liquid on Mars. When you look at any design out of SpaceX, you need to keep in mind the fact that Elon himself drives the requirement

There's no pool of inert liquid on Mars. When you look at any design out of SpaceX, you need to keep in mind the fact that Elon himself drives the requirement of 'this has to help humans get to Mars'. It extends through the Falcon, the Dragon and a whole heap of other aspects of what they do.