shifting from park to reverse with engine running

I parked the Jeep exited with the engine running and drivers door open to feed a buddy cat and stand guard against the pigeons. was just about finished when I looked up and the car was moving in reverse. I tried to jump in tp stop it before major damage was done to 2 new trucks parked properly. thinking I was 19 instead of 90 and the door hit my leg knocking me to the pavement hitting my head I instinctively rolledaway from the car as the front drivers tire missed my head by MAYBE 1". I was dazed and couldn't get up and layed there about 2-3 minutes when a young man from across the street who was getting on his motorcycle to go to school saw me and came over and helped me to my feet. The car was not visible and then I heard the sound of it's engine running. Amazingly it had went around one of the trucks the made a severe right hand turnmissing the other truck, went between the 2 homes and High-centered on the concrete air conditio0ning pad missing the compressor by a foot. The men from AAA said in 28 years they had never seen anything like it. I hate this killer machine! Verne Batchelor