Missile Weapons and Melee Combat
This rule change is an interesting addition, proposed by one of the players. It has been modified only slightly.
When firing a missile weapon into combat, that attack role usually incurs an extra -4 as a circumstance modifier because the target is moving in response to attacks from others in adjacent squares.
This modifier will continue to apply, but if the -4 modifier is what causes the attacker to miss their opponent (i.e. the dice roll plus all modifiers would normally have hit, but the application of the extra -4 causes the shot to miss) then the attacker must select one of the other participants in the original target's melee at random (both friend and foe included - as long as they are adjacent to the original target, or have reach weapons that bear) and make a new attack roll against them. This second roll is adjusted with the same modifiers as the original roll except that the -4 'firing into melee' combat modifier does not apply.
If the attack hits, then calculate damage in the normal way. If the damage could be factored in a choice of ways, then the choice must be made as though the original target was being hit.
The effect here is that firing into melee combat is not a safe option, there is a chance (albeit a slim chance with well-armoured friends) that you could hit a friendly target. And in trying to do your best, you may find that back-stab bonuses and/or critical hit bonuses also apply.