(1) If an officer reasonably believes that a person is unlawfully detained in such circumstances that his life is in danger, the officer may enter any premises for the purpose of ascertaining whether the person is detained there.
(2) In this section "officer" means -
(a) a member of Her Majesty's forces on duty, or
(b) a constable.
(3) A dwelling may be entered under subsection (1) only by -
(a) a member of Her Majesty's forces authorised for the purpose by a commissioned officer of those forces, or
(b) a constable authorised for the purpose by an officer of the Royal Ulster Constabulary of at least the rank of inspector.