Chapter 4 Type of Tunnel
(B) Doored and shored
Thick steel or composite doors need to be opened and shut with relative ease. With their frames and surrounding concrete means that to install them it's necessary to dig a much larger tunnel (ie one which you can crawl through on your hands and knees rather than on your belly ). More shoring will thus generally be needed. The more doors that are installed the longer the tunnel takes to evict. Though of course this design is a non starter if there isn't a local friendly metalworker to make them. Combining both of the aforementioned is the best of all. The more variation in the design the harder it is to evict. A new different obstacle will cost the authorities more time and money as the bailiffs will leave the tunnel and have a meeting to consider how to safely tackle it. Constant variation in design should hopefully mean many such meetings. You want them to get a headache not a routine.
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