We give the twelve men a boat and supplies, and watch them sail back to the surface world. The left just in time!
Because as we go further into the Earth, more of the Earth is "on top" of us, and gravity goes down. Every hour the waves grow larger. Then the lightning and hurricanes begin!
It must be due to the changing temperature and lower gravity or the Earth's magnetic field! Every wave is like a mountain, or a whirlpool, and we're in the middle of it! Is this the end?