—(1) Two of the visitors of a psychiatric institution, upon the recommendation in writing of the principal officer of the institution, may permit a patient to be absent from that institution for as long as they think fit.
(2) If before the expiration of the period of absence, a certificate of 2 designated medical practitioners working in the psychiatric institution that it is no longer necessary that the patient be detained in the institution for care and treatment is forwarded to the principal officer or the visitors of the institution, the patient shall be deemed to be discharged from the institution.
(3) If the patient does not return to the psychiatric institution within 28 days of the expiration of the period of absence, and no such certificate referred to in subsection (2) has been received, the patient may be retaken as in the case of an escape.
(4) The principal officer of a psychiatric institution may permit a patient of the institution to be absent from the institution for any period not exceeding 6 months, and if upon the expiration of the period of absence the patient does not return to the institution the patient may be retaken as in the case of an escape.
(5) Without prejudice to the generality of subsection (4), the principal officer of a psychiatric institution may, where it appears that a patient detained in the psychiatric institution requires treatment for an illness other than mental disorder, direct that the patient —
reside in and be kept in the custody of any other hospital for a period of time for the purpose of receiving such treatment; and
if it is necessary in his interests to do so, continue to receive treatment for mental disorder in that other hospital during that period.