 Hearn and Bentley also argue that the premise is similar to that of the first episode.Bentley writes that "Pit of Peril" "somewhat slavishly follows the formula of 'Trapped in the Sky'", comparing the plight of the experimental Sidewinder to the sabotage of the new "Fireflash" airliner in that episode.He describes the Mole as being "lifted directly" from Edgar Rice Burroughs' novel "At The Earth's Core" (1914).