If upon the expiration of a reasonable time after the proclamation is made, or after the making of the proclamation has been prevented by force, twelve or more persons continue riotously assembled together, any person authorised to make the proclamation, or any police officer or any other person acting in aid of that person or police officer, may do all things necessary for dispersing the persons so continuing assembled or for apprehending them or any of them, and if any person makes resistance, may use all such force as is reasonably necessary for overcoming such resistance and shall not be liable in any criminal or civil proceeding for having, by the use of such force, caused harm or death to any person.