The standard hp for a regular human, which for the setting is probably in better shape than the office honed bodies of today, to be incapacitated for combat and eventually die is about 4 (depending on edition).
There is maybe one way a trained human could perform a combat biting attack that would render someone unable to fight back, which is a bite to crush the wind pipe, and with all anatomical protection in place, it seems unfeasible even if they would have the jaw strength for it.
I came to say precisely this.
The standard hp for a regular human, which for the setting is probably in better shape than the office honed bodies of today, to be incapacitated for combat and eventually die is about 4 (depending on edition).
There is maybe one way a trained human could perform a combat biting attack that would render someone unable to fight back, which is a bite to crush the wind pipe, and with all anatomical protection in place, it seems unfeasible even if they would have the jaw strength for it.
maybe it should be 1d2 then - can only deal 4 points of damage on a crit