Earth is only a distant memory to John Carter, a memory he wants to keep distant. Mars is savage and brutal, but far more honest than the blue planet he left behind. If Carter allows Tarzan to return to his home planet, it could lead to an earthly invasion of Barsoom . . . an invasion which Carter fears his adopted home would be hard pressed to stave off. So, to ensure he never has to see Mars compromised by humans, Carter will see that Tarzan is buried six-feet under its surface.
