I don't understand it much, but it did occur to me when I was reading it that if equipment can detect the light emerging the tunnel earlier, then it has a physical effect on the world. And perhaps that physical effect could be used to make a novel ion thruster or solar sail that is 300x more efficient. E=mc2 thus c=sqrt(E/m) and m for photon is constant -- proportionally higher c is balanced by a more efficient E?
Might be useful for a lot of things if the research holds up. Maybe we could get a realtime video feed of Mars, instead of being 15 minutes or so behind :) That would make exploration and space development and such a lot easier.
Incidentally, if we can't assume c as a constant, we might not be able to assume m as a constant for photons either.