A person may not be convicted of an offense, based upon conduct in which he engaged, because of the use or threatened use of unlawful force upon him or upon another person, which force or threatened use thereof a reasonable person in his situation would have been unable to resist. This defense is not available when a person intentionally or recklessly places himself in a situation in which it is foreseeable that he will be subjected to such force or threatened use thereof. (Ord. 200 §1, 1982)