Before using military force in the dispersion of any riot, rout, tumult, mob, or other lawless or unlawful assembly or combination mentioned in this chapter, it shall be the duty of the civil officer calling out such military force, or some other conservator of the peace or, if none be present, then of the officer in command of the troops or some person by him deputed, to command the persons composing such riotous, tumultuous, or unlawful assemblage or mob to disperse and retire peacefully to their respective abodes and businesses; but, in no case, shall it be necessary to use any set or particular form of words in ordering the dispersion of any riotous, tumultuous, or unlawful assembly, nor shall any such command be necessary where the officer or person, in order to give it, would necessarily be put in imminent danger of loss of life or great bodily harm, or where such unlawful assembly or riot is engaged in the commission or perpetration of any felony, or in assaulting or attacking any civil officer or person lawfully called to aid in the preservation of the peace, or is otherwise engaged in actual violence to any person or property.