Boat.

This is coolbert:

Crazy indeed!

Herewith some additional information, the Soviet era nuclear-powered military underground borer. Thanks to the Internet web site English/Russian.

"THE CRAZIEST SECRET MILITARY PROJECT OF THE USSR"

"The subterranean nuclear combat boat was probably the most fabulous secret military project of the USSR."

AND was the topic of a previous blog entry.

I doubt very much that the crew of the nuclear-powered borer would be able to exit the vehicle into a well lit subterranean cavity. 

"When [the] Wehrmacht [German army] was defeated the documents came to the USSR. On their basis in the time of N. Khruschev Soviets finally created an acting model of a subterranean boat. During its first test in the Urals the boat sailed along the mountain with a speed of a pedestrian. During the second test the boat exploded and turned to be immured together with the crew in the mountains. In the time of Brezhnev [he] having understood all foolishness and mercilessness of the project it was eventually canceled."

"immure - - verb 1.to enclose within walls. 2. to shut in; seclude or confine. 3. to imprison. 4. to build into or entomb in a wall."

There you have it. Project canceled. Borer and crew gone. Borer vehicle exploded. Crew and border trapped without any chance of rescue way underground.

And as to the amount of nuclear spew as emitted by the borer while operational? Contamination potentially immense. This explosion was not necessarily an atomic detonation but a melt-down as that term understood?

Even the entire concept of subterraneans on paper suspect? Easier, cheaper, and quicker way to do the same damage as a bomb-laden subterranean boring through the earth?

coolbert.