When I read this argument about the purpose of these tunnels, I can't help thinking of the questioning of Nathaniel Whatsisname in Pickwick Papers:

"On this question there arose the edifying brow-beating, customary on such points. First of all, Mr. Winkle said it was quite impossible for him to say how many times he had seen Mrs Bardell. Then he was asked if he had seen her twenty times, to which he replied, 'Certainly--more than that.' Then he was asked whether he hadn't seen her a hundred times--whether he couldn't swear that he had seen her more than fifty times-- whether he didn't know that he had seen her at least seventy-five times, and so forth; the satisfactory conclusion which was arrived at, at last, being, that he had better take care of himself, and mind what he was about."