Of course we all know that as the PIC we have the automatic powers of a Constable to subdue passengers using any necessary force (aka fist, fire axe, fork, bullet) to protect the safety of the aircraft and those on board.
For those that think it can't happen, a mate was taking some disabled people for a fly in a chartered 182 when the guy in the rear who had a condition due to a truck accident years earlier, decided he was going to attack the pilot from behind. My mate literally crapped his pants as he had nothing he could do to defend himself other than work with the mans carer to subdue him.