In an emergency arising from attack, war, mob violence, or similar violence, or from a natural disaster due to the elements, such as earthquake, fire, explosion, wind, or water, any or all employees of the city may be directed by their acting department head, or directly or indirectly by the director of emergency services, to go outside the city limits, under approved mutual aid agreements, to perform certain work or services in connection with such emergency. Each and every employee required to perform such work shall render such service under such circumstances to the best of their ability, and if injured in the course of complying with these requirements and directions, they shall be deemed to be injured in the course of employment and shall be entitled to workers' compensation therefor as provided by law. (1962 Code § 2-6.404)