Strikes me more that the potential for damage is higher here. A pretty small explosive charge would compromise part of the tube, and then what happens to the pods zipping along at 2,500mph inside them when the air comes rushing in? For that matter, if they did have an underwater tube connecting London and NYC, the water would come rushing in and you know that's not going to end well.

It sounds pretty cool - it's the kind of sci-fi thing I'd love to see in the real world, but I can't believe it's as easy or as cheap as they're making it sound here.