 Davies based the episode on the traditional disaster film format . He was highly influenced by the 1972 film The Poseidon Adventure : he considered " [ turning ] the spaceship upside down " before cutting the concept for monetary constraints ; and the character of Foon Van Hoff ( Debbie <unk> ) was heavily based on Belle Rosen ( Shelley Winters ) . He diverged from the trope in its climax ; the format of Doctor Who dictated the requirement of an antagonist : Max Capricorn , whose plan was to sabotage the ship as part of an insurance scam . Davies based the portrayal of Kansas in the 1939 film The Wizard of Oz as an analogue for Sto . 
