Yes Denver and surrounding areas are corrupt to the core, it's all Dem controlled.
Look at the distance between Buckley and Denver International. 10 miles and NOTHING between them of significance. Not hard to run a large tunnel between the two. A large bore machine can knock that out quickly.
Also recall that Denver Intl replaced Denver Stapleton and it was very close to the line between Den Intl and Buckley - so they could join an existing tunnel from Stapleton to Buckley. A tunnel is not out of the question at all, even make sense. Buckley does have various classified ops that requir lots of data, so the idea of a large data repository of some type there is not unreasonable.