Doctor Who Episode 2.09 The Satan Pit

The Doctor and one of the Earth crewman become stranded deep under the planet, near an even deeper chasm. The Doctor decides to make a leap of faith, while depending on Rose, still with the rest of the crew trying to leave the mysterious planet, to do the right thing. Only if they both succeed in what they need to do, will they all survive the evil intentions of the creature that may be the real Satan, whom is intent on reclaiming his throne on Earth.