Erm ,
I know this might sound a bit stupid, but what about the lorry driver. Surely he is the person that ran the man over NOT the helicopter. As I understand it you are required by our laws to drive with due care and attention, but I bet the lorry driver will be a witness to say the helicopter blew the man into the path of his vehicle.
Sadly there is a man in hospital through no fault of his own, but he could just have easily fallen and had the same consequence.