From the look of the bike, it seems to me that he was only riding it for the purpose of taking a video; demonstrating the concept and engine design. It's also a point to note that he is riding quite slowly.
I agree that the bike should have brakes and i'm an advocate of motorized bicycles being fitted with the largest and most powerful disk brake systems on the market, but in this case the bike looks like nothing more than a demonstration of concept rather than a usable form of transport.