What a disgrace British royalty has become over the centuries. Had Henry V been in the car, there would have been several dead protesters.
The Prince put his wife on the floor of the car and his own body between her and the attackers. He and the security officers remained in the car so it could continue moving.
There were some major mistakes made here, but if you think he could have realistically done anything else besides shield his wife, I think you are wrong. He wasn’t armed. His security were and they didn’t seem to feel the need to use force either - why, I don’t know.
I have stood within yards of the Prince as somebody charged towards him firing a pistol. He remained calm and composed and faced the danger. He’s done this before. His job in this situation - what he is trained to do - is exactly what he did. Stay within security or stay where you are until help arrives. People are willing to risk their lives to protect him if need be - they expect him to be where he’s meant to be, or he risks wasting that.