(a) Whenever any shot is fired or missile thrown at, against, or upon any force of the organized militia or against any officer or member thereof assembling or assembled for the purpose of performing any duties under this chapter, it shall forthwith be the duty of every person in the assemblage from which the shot is fired or the missile thrown to disperse immediately and retire therefrom without awaiting any order to do so.

(b) Any person failing to retire immediately from any assemblage after a shot has been fired or a missile thrown in any manner mentioned in subsection (a) of this Code section shall be guilty of a misdemeanor; and any person so remaining in the assemblage after being duly commanded to disperse as provided in Code Section 38-2-303 shall be guilty of a felony and, upon conviction thereof, shall be punished by imprisonment for not less than one nor more than five years.