you can't just shift the prius into neutral...IIRC I read somewhere it doesn't allow you do that if the car is at certain speed or RPM.
and it takes 3 seconds of holding start/stop button to turn off the car...that can be the longest 3 seconds of your life when your car is going 100+mph
These cars are having something go electronically wrong with the ECU where the Fail safe is shorting and causing this issue. Someone on some news program can recreate the whole situation with the acceleration on a regular 2010 Toyota vehicle that was supposedly already fixed. Seems to me that their is a much more bigger issue with the cars.