(1) Unless inconsistent with other provisions of chapter 743, Oregon Laws 1971, defining justifiable use of physical force, or with some other provision of law, conduct which would otherwise constitute an offense is justifiable and not criminal when:
(a) That conduct is necessary as an emergency measure to avoid an imminent public or private injury; and
(b) The threatened injury is of such gravity that, according to ordinary standards of intelligence and morality, the desirability and urgency of avoiding the injury clearly outweigh the desirability of avoiding the injury sought to be prevented by the statute defining the offense in issue.
(2) The necessity and justifiability of conduct under subsection (1) of this section shall not rest upon considerations pertaining only to the morality and advisability of the statute, either in its general application or with respect to its application to a particular class of cases arising thereunder.