Oh I see what you're saying. How strange. So if you're brought to 0 you remain alive til -10 (or optionally if reduced to -3) but if you're reduced to -4 you just die instantly? Mea culpa, that is not how I read it at first. What a strange rule...
Right. Ja. He defines a safety zone to allow for the possibility of characters being knocked unconscious and bleeding without being instantly snuffed. But it's not guaranteed. If you take a big enough hit, even under this optional rule, and get dropped past the unconscious and bleeding range, you're still just dead.
Right. I find the Gygax rule seems to often be misread. (As I posted upthread, I don't know the 2nd ed rule.)
Gygax's rule, as I understand it, is that being dropped to zero is unconsciousness and bleeding (with a lower limit of -10) while being dropped below zero is death. There is an option to expand the "safety zone" to -3. I think the expanded safety zone kinda works in a system where the damage range is often a d8 or thereabouts, and so the prospect of falling from consciousness to the safety zone is realistic. Obviously in a game with 3E or 4e or even 5e damage spreads, having such a narrow safety zone would make no sense!
It's not spelled out what happens to a character who is in the unconsciousness zone and takes more damage (other than from bleeding), but I think it makes sense that they die. This is reinforced by the text that
@Garthanos has been pointing out: once someone falls unconscious, then if restored above zero hp they are comatose for 1d6 turns (ie up to an hour), and then have a period of enfeeblement and recovery regardless of what happens to their hit point total. During this period, which is described as "a full week, minimum" the character may "move slowly to a place of rest and eat and sleep" but "cannot attack, defend, cast spells, use magic devices, carry burdens, run, study, research, or do anything else" (p 82). Only a Heal spell can alleviate this condition. Being
unable to defend implies to me that any damage taken is fatal.
Unearthed Arcana had two rules that interact with the negative hit point space. One was a quirky rule for good cavaliers, who can function at negative hit points: instead of falling unconscious they cannot further attack but must rest, may bind wounds, and may seek further healing. This is not spelled out in any further detail, but if using this rule I would treat the cavalier at negative hit points as being in the same condition as the person who has been restored from unconsciousness to above zero hp.
The other UA rule is the 3rd level spell Death's Door, which brings a creature in the -1 to -9 hp range to zero hp, and stops bleeding, for 1 hour/level. The spell text is not perfectly clear: it says that the target of the spell, having been brought to zero hp, can have hp restored and be brought to consciousness by other healing magic. The way we interpreted it back in the day is that it allows the character to be restored without suffering the period of coma and subsequent need to rest for a week.
(Only very vaguely related: if I was to play AD&D these days I would move Cure Serious Wounds from 4th to 3rd level (leaving it at 4th level for Druids), Restoration to 5th level (ie the same as Raise Dead) and Regeneration to 6th (ie the same as Heal).)
