It doesn't matter if you don't have yahoo's with guns there, the problems with the vacuum being breached can come from dozens of other sources including thermal expansion,etc. At this point the best solution to the stresses due to thermal expansion might be to build the hyperloop underground where the temperature remains more or less constant and is far less subject to rapid expansion due to rapid heating and cooling.But then there is still a host of other problems with no easy solution which will have to be overcome. Don't get me wrong, the hyperloop is a great idea and may someday come to fruition but as it stands there are some major obstacles with no easy solutions that will have to be overcome. Basically we need to create an outer space like environment contained within a 500 mile tube and propel a turbine powered capsule through it close to the speed of sound and at the same time do it inexpensively and assure near absolute safety. The obstacles that had to be overcome to produce high speed rail service are nowhere near the obstacles that have to be overcome to produce safe, reliable, speed of sound hyperloop service. Will it ever become a reality ? Yeah, I think that eventually it might. I certainly wouldn't give up on the idea. But it's going to taken quite a bit of time, thought and work and perhaps even advanced future technologies. In the meantime and until the hyperloop is feasible I think it would be much more practical and far less expensive to build out a high speed rail service. And for the United States a modern high speed rail service would be a giant step forward.Most of our present rail service is basically the same technology that was around in the 19th century. We presently don't have anything here that matches the modern high speed rail you have in Europe.