I played a game tonight where a Ducal Militia RL Spec attempted an AP shot at a group of ISC Gendarmes. Becaus of smoke and range, the effective roll needed to hit was -1. Should the shot have been allowed (we ageed that the shot was allowed, and that actual damage would be calculated from the negative number, i.e.: the Ducal RL Spec rolled a 4, missing by 5, therefore, the resulting damage was 5). However, in allowing the shot, we also opened the door to the critical hit (natural 1 on a d20). How is this to be played in the future?