It's not crazy talk. The truth is they likely belong both above ground and below ground, depending on urban density or geography. And tunnels tend to have escape ladders every so many feet.
Elevated train platforms may have escape ladders, but I thought the Hyperloop tube was depressurized and the car within it needs to be pressurized. This poses a problem for the escaping passengers before they reach the ladder.
It's only a partial vacuum from what I understand. I'm not sure what kind of difference that makes but presumably it would be easier to depressurize in an emergency.
