While i was driving 15 mph on a private road, i suddenly lost power steering and power brakes. i managed to bring the car to a stop, but i couldn't engage the parking brake, shift out of drive, or turn the car off. the electronic shifter, electronic parking brake, and electronic starter were all unresponsive. i saw numerous warning messages on the dashboard. one of them said "service shifter. continue in d. do not shift or turn engine off", but it didn't tell me what i could do to return the car to a safe state. i kept my foot on the brake and called roadside assistance. i asked them what my options were, and they told me that i could wait until the car runs out of gas. i'm not sure what i did, but i eventually got the care to shut off, but it stayed in neutral, so i still couldn't take my foot off of the brake. eventually a tow truck arrived and got the car in to park by entering the cargo area by climbing through the back seat,disconnecting the battery, and reconnecting it.