Intermitent means it comes and goes. They had several intermitent failures in the days prior to the accident involving the rat overtemp. Since the R2-5 relay controlled both rat heater and TOWS the TOWS would have failed too if checked at that time. It was the only relay of the eight or so that failed, controlled by the L nose gear oleo switch. The other relays on the same oleo circuit worked fine. The only way the rat heater can get power is through the R2-5 relay. Many mechanics must have missed the connection that the only way that could happen is if the relay was in de-energized air mode. The MEL they used was for an inop RAT heater. Obviously the heater was working fine but shouldn't have been powered on the ground. MEL's have to be read very carefully to make sure what you are doing is the intent of the MEL.