The secret tunnel thing seems quite a consistent stretch of imagination to me, mr. Jim
(every time someone tries to explain something strange or "weird" of the game with huge stretches of imagination, like the poisonous-gas-inhaled thing of the poison arrows
, it reminds me that Simpsons' episode in which the actress of Xena says every strange thing in the series, like the horses she's riding changing race, is explainable as it has been done by a mage
somebody remembers?)