Tennessee Code Title 58. Military Affairs, Emergencies and Civil Defense § 58-8-107

(a) This chapter does not create a duty on participating governmental entities to respond to a request for aid or assistance nor to stay at the scene of an occurrence or emergency for any length of time. Upon receipt of a request for aid or assistance, a potential responding party shall determine whether and to what extent it will provide the aid or assistance. If the potential responding party determines in its complete discretion that it is not in its best interest to provide aid or assistance, it shall notify the requesting party of its decision as soon as possible. If the potential responding party determines that aid or assistance can be provided, it shall communicate the following information to the requesting party as soon as possible:

(b) The responding party may withdraw aid or assistance at any time. The responding party shall notify the requesting party as soon as possible of any decision to withdraw aid or assistance.

(c) The provisions of this section that require certain actions are directory rather than mandatory and do not create a public or special duty on the part of any participating governmental entity.

(d) In addition to any agreement for mutual aid made under title 5 or title 12, a governmental entity is authorized to respond to a request for mutual aid for emergency medical services under § 58-8-105(e) from a county that is contiguous to the requesting county or governmental entity for occurrences that involve serious injuries or possible loss of life in instances that might not reasonably lead to a declared emergency. A county is authorized to enter into a mutual aid agreement under title 12 to permit routine and automatic approval of and response to such requests.