There is an artifact of sequential action built into the initiative system, such that no two actors in an encounter can charge each other at the same speed and clash at the midpoint between them, and that one actor who delivers a kill shot to another character having a lower initiative can prevent that one from ever doing anything.
As befits their role as mobile XP generators, monsters are usually on the losing side of these quirks in the system. However, in situations of epic combat where (for example) a PC is dueling a major villain and "simultaneous" attacks can bring added drama, some kind of 'shot in motion' rule (see here http://amtwiki.net/amtwiki/index.php/Shot_In_Motion for a LARP example) would help create this.
I'm not really sure how to solve the "simultaneous movement" problem without breaking down each round into half-actions (which can get gnarly for new players), but simultaneous standard actions and attack actions are somewhat easier to quantify, IMO. Here is an attempt to quantify these ideas in rule format.
For absolute consistency, similar exceptions should probably be made for other effects that incapacitate a character. I am wary of multiplying such exceptions for every condition that might constrict available actions (let alone invoke penalties). So I think we can accept a little inconsistency here and let 'shots in motion' take effect only in life-or-death situations.
As befits their role as mobile XP generators, monsters are usually on the losing side of these quirks in the system. However, in situations of epic combat where (for example) a PC is dueling a major villain and "simultaneous" attacks can bring added drama, some kind of 'shot in motion' rule (see here http://amtwiki.net/amtwiki/index.php/Shot_In_Motion for a LARP example) would help create this.
I'm not really sure how to solve the "simultaneous movement" problem without breaking down each round into half-actions (which can get gnarly for new players), but simultaneous standard actions and attack actions are somewhat easier to quantify, IMO. Here is an attempt to quantify these ideas in rule format.
* A conscious character reduced to (non-lethal) negative hit points before having taken his turn in the current round takes the staggered condition until the end of his turn (and then is reduced to dying). But if he has already acted in the current round, then he is immediately reduced to dying.
* A conscious character reduced to lethal negative hit points (that is, negative hit points equal or greater than his Constitution score) before having taken his turn in the current round takes the staggered condition until the end of his turn (and then dies). But if he has already acted in the current round, then he immediately dies.
* A temporary staggered condition isn't applied if the character being threatened with death is otherwise incapacitated and unable to act (such as by being confused, cowering, dazed, helpless, paralyzed, stunned, or otherwise unconscious). In such cases the dying or dead condition is immediately applied to the victim during the aggressor's turn.
For absolute consistency, similar exceptions should probably be made for other effects that incapacitate a character. I am wary of multiplying such exceptions for every condition that might constrict available actions (let alone invoke penalties). So I think we can accept a little inconsistency here and let 'shots in motion' take effect only in life-or-death situations.