While at an assigned place of duty, a person employed as a Dallas security officer:
(1) is vested with the power of arrest for misdemeanor breaches of the peace, to prevent the consequences of theft and felonies in the officer's presence, limited to situations arising out of enforcement of the officer's specific duties and further limited to the specific authority contained in the officer's warrant of appointment;
(2) may carry and use a firearm when authorized by the city marshal; and