Thought for the day. If c represents an asymptote in the relativistic equations for time, mass, length in the direction travelled etc, assuming a particle on the brink of crossing that asymptote could pass it, the first effect of time's arrow reversing would be that it would immediately jump back the the point in time just before it crossed it....
Or something bizzare. Assuming you can get past the weirdo effects of the undefined (tends towards infinite) mass etc before you crossed that asymptote.
There's nothing random about cherenkov radiation. It's cool :-) What I can only describe as an "optical boom" :-D