Story:
Hi guys, I'm 17. I get my license in August, and got this beautiful car for my birthday so I could be comfortable with manual, and so I could learn more about cars before then. Anyways, this car usually sits in my driveway and I was super excited that I was going to be able to drive it (Was going to barbers and out to dinner). However, its parked on my steep driveway. It sits in 1st, Ebrake up, and two bricks behind it. My mom had gotten in it first and was in it, and forgot to take the two bricks behind it out. She got out, and removed the bricks - then the car started rolling back. This motherfucker sped up REALLY fast. My mom managed to get mostly out of the way, but the open drivers door hit her, knocked her over, and went over her (somehow), and took out our mailbox. The car kept going and went into my neighbors rocky ditch, though the way it stopped, it didn't scraped. The picture linked is where it got pulled out by the tow truck. Regardless of the car, I called 911 and took car of my mother first. Drove her to the hospital as soon as it got pulled out (EMS checked her out first she didn't need to be rushed to hospital). Broken cartilage in her ribs and severe bruising all over. It could have been a lot worse.
Regardless, since this is a mustang subreddit, I need some help with questions about the car. First, why did it even roll? My guess is that the clutch master cylinder lost pressure, as I've had to pump clutch a few times to shift occasionally (Please correct me if I'm wrong, I'm learning). And the ebrake is finicky, so it might not have caught when it was first parked. Does this sound right?
Also, if anyone knows where I could get a 05 mustang v6 drivers door in the Raleigh, NC area, let me know. The fender took a hit as well but it's not bad from what I've noticed. I don't think theres any other damage, it still drives and was still on when it stopped in their ditch. Nothing leaking, nothing smelling where and I popped the hood and nothing looked out of order. Tires def needs to be aligned as well.