(1) No act of a person constitutes an offence if the act is done under duress of circumstance.
(2) A person does an act under duress of circumstance if—
(a) he or she knows or believes that it is immediately necessary to avoid death or serious injury to him or her or another person he or she is bound to protect;
(b) the danger that he or she knows or believes to exist is such that in all the circumstances he or she cannot reasonably be expected to act otherwise.
(3) It is for the defendant to show that the reason for his or her act is such knowledge or belief as is mentioned in subsection (2)(a).
(4) This section does not apply to a person who knowingly and without reasonable excuse exposed himself or herself to the danger known or believed to exist.
(5) If the question arises whether a person knowingly and without reasonable excuse exposed himself or herself to such danger; it is for him or her to show that he or she did not so expose himself or herself to such danger.