Q 160: A character with the Diehard feat decides to stay conscious and disabled after being brought to -2 hp's. He then takes 1 point of nonlethal damage. Can he stay conscious, or is he knocked out?
Q 160b: Similar question, but it is a Frenzied Berserker. He's immune to the effects of nonlethal damage while in his frenzy, but then it ends. Does he fall unconscious, or does his Diehard feat keep him up, if he wants?
A160: I can't give you any definite answer on that. Technically, either Diehard lets you ignore nonlethal damage at negative hit points, or it only stabilizes you at negative hp but doesn't let you remain conscious (thus not working as intended). My reasoning for this is that even if you don't have any nonlethal damage, you still have 0 nonlethal damage, which is greater than your hp when at negative hp. Thus, you should be unconscious from the nonlethal damage anyways. If Diehard works as intended, you stay conscious anyways, because you're at negative hp. If it works as it stupidly, RAW, does, then you replace the dying condition with being conscious, and then you fall unconscious anyways from the nonlethal damage.
As a ruling, I would suggest that Diehard also not make you fall unconscious until your nonlethal damage equals or exceeds your hp + 10 (so that you only fall unconscious at the nonlethal equivalent of -10 hp, same as you would die at). That's just a house rule/suggested fix/clarification of intent, though.