I tried to open the back of the vehicle and i could not since i did not press long enough. then i tried to do the same from inside the vehicle but again i could not since again i did not hold the button long enough(i bought this vehicle for my wife and i was driving it for the second time due to snow). i thought maybe i should turn off the vehicle and try again since my logic was if the truck is running due to safety reason the back door might not be opening. as soon as i turned off the car with it started to roll backwards since it was on slight slope. our 3 daughters were nearby and i was scared they might be near the back side but thank god they were on side of the truck. i kept running with the truck till i can get in it and stop it. i got hurt on my knees and blood started to come but i was lucky enough to stop it. i want infiniti to look into this issue asap since i don"t want anyone hurt or even worse. it is 2017 infiniti qx80. see attached video.thank you. (xxxx) owner of the vehicle. parts of this document have been redacted to protect personally identifiable information pursuant to the freedom of information act (foia), 5 u.s.c. 552(b)(6) *dt consumer stated car started to roll back while in park. *jb