I cannot speak to the bulk of the question, but there is one thing you can go to the bank with, and that is that electrons never, ever, travel at the speed of light. Period!
They don't even travel near that speed in normal daily interactions of even most fearsome types here on earth.
The most potent Beta particles ejected in nuclear events are still short of 99% of the speed of light. More energy just adds more nines...even to the billions of electron volt class electrons.
Richard Hull
Created on Tuesday, June 12, 2001 8:44 PM EDT by Richard Hull