Automatic Transmission problems of the 1999 Mercury Mystique

Car was parked in motel parking lot. I entered car at 6:55am to move car by our room to pickup bags. I had my foot on brake, started engine and shifted into reverse. The car jumped rearward at a high speed. I had not put my foot on the gas pedal. The car hit a telephone pole (about 8 feet behind were the car was parked). My body went rearward when the car hit the pole. At this time, I had my hand on the shifter (floormount) and it pulled the car into forward gear. The car shot forward and slammed into a brick column directly infront of were I was parked. I tried to turn off ignition and hit the brake but I couldn't effect the forward motion. I saw the car hit the pole and my forehead hit the steering wheel. The airbags did not deploy. I was told at the hospital that you need to be going 35mph or faster for them to deploy. Don't know about that. I have never had any accidents before. I know that I did not put my foot on the accelerator when I engaged reverse. I could hear the motor revving higher than normal. I was accelerating when the car was going forward.