I saw that not too long ago and it still amazes me...this is a perfect example of why you don't stand in front of someone that is moving a vehicle, much like handing someone a firearm without checking it for first for ammo, empty chamber, magazine, de-cocked, etc.
This is also EXACTLY why I never turned my back on any drivers or trusted them the 31+ years I worked in the roadway on traffic signals.
The second car thought he was pressing the brake paddle. I knew someone that was killed in the 80's this way in front of a Lil Champ store in Florida. As the result of the lawsuit, the company put in the bollard posts in front of all their stores.