Mass. Gen. Laws ch. 126, § 27

If a jail or other county prison or any building near thereto is on fire, or if a bomb threat has been received, or there is reason to believe a bomb threat or similar threat exists, and the prisoners are exposed to danger thereby, the sheriff, jailer or other person in charge of the prison may remove them to a safe place, and there confine them as long as necessary to avoid the danger, and such removal and confinement shall not be deemed an escape of the prisoners.