Lady Christina makes her way down the shaft in the Tritovores ship as she tries to get hold of the crystal power source to make the ship fly again. When The Doctor finds the Cup of Athelstan in Lady Christina's bag he calls her a thief, but Christina prefers to call it liberating! Watch this action-filled clip from the BBC Doctor Who special Planet of the Dead. Watch more high quality videos on the new BBC Worldwide YouTube channel here: http://www.youtube.com/bbcworldwide