...How do you accidentally kick someone? Literally the only way to hit someone is to say "I hit that guy". Plus even if you did somehow do it, it should have dealt nonlethal damage, which is HIGHLY unlikely to result in death (you need to deal roughly DOUBLE the damage normally required to kill someone). I think your GM is just fucking with you. Our Barbarian had hit him in the head with a mace just before I kicked him. He did 6, I did 4, guy's HP was 10. Which puts him at 0 HP...meaning he's not even Unconscious yet, much less dead. He's at 0 HP and Staggered, but still able to act (though taking a Standard or Full Round action deals 1 point of damage to him, dropping him to -1). You have to get him to -Con score to actually KILL him, which is probably at least 7, so he's far from dead. I'm pretty sure all editions of D&D share this rule. Unless you're playing 5E and that changed it?