RCW 72.23.050

The superintendent shall not be required to attend any court as a witness in a civil or juvenile court proceedings, but parties desiring his or her testimony can take and use his or her deposition; nor shall he or she be required to attend as a witness in any criminal case, unless the court before which his or her testimony shall be desired shall, upon being satisfied of the materiality of his or her testimony require his or her attendance; and, in time of peace, he, she, and all other persons employed at the hospital shall be exempt from performing military duty; and the certificate of the superintendent shall be evidence of such employment.