WOW.
Poor driving skill coupled with panic. If I was to guess, I would say the throttle stuck. The vehicle is too new to have a cable. The throttle is computer controled. That means a piece of unsecured cargo ended up in the drivers footwell.
The first thing that comes to mind is a water bottle under the brake pedal. At this point you have no brakes. The other would be something landing on the gas pedal. A large water bottle could cover both pedals causing this when you hit the brake.
Another thought is something striking the driver from behind.
In reality, going up the hill, the driver should have let off the gas when he started losing it half way up. Any way you look at it, something bad happened.
