Mushuku Mono

My friend has a 2003 cavalier (automatic) and when she was pulling into church today she has to stop and put it in reverse for whatever reason and when she did it did not go in reverse and acted like it was still in drive, even though the shifter showed it was in reverse. We got it into the parking spot and shut the car off and put it in park but it just wants to roll and even with the car in park it will not start at all.
It doesnt make sense to be because if it was just the shift cable had broken, when the shifter was put in park it should still start, but it doesnt even crank. Is there another safety swich in the trans of the newer cavies? What else could have made the car stay in drive and not turn on even though the shifter will go through each gear?