(b) In a prosecution under AS 11.41.110(a)(3), it is an affirmative defense that the defendant
- (1) did not commit the homicidal act or in any way solicit or aid in its commission;
- (2) was not armed with a dangerous instrument;
- (3) had no reasonable ground to believe that another participant, if any, was armed with a dangerous instrument; and
- (4) had no reasonable ground to believe that another participant, if any, intended to engage in conduct likely to result in death or serious physical injury.