I don't know if it's an urban legend or not, but I heard that they put a special cover on the light in his retaining cell because they were afraid he would find some way to "hack" his way out with the wires.
That would be an entertaining plot device in a spy movie: spy gets captured, finds that power fluctuations occasionally flip a bit in the memory of the security system, uses the light in his/her cell to flip all the bits corresponding to the door locks...