When a character is this badly injured, even the best medical treatment is not necessarily enough. A character in the negative hit point condition is considered mortally wounded, and only a very skillful physician can save the character's life.
To accomplish this rescue, the injured character's condition must first be stabilized. The healer must make a Healing skill check at -1 for every hit point below zero. Thus, a character at -10 hit points could only be saved if the healer makes a successful healing check at -10. Truly, this is a Herculean effort. If the check is successful, then the character's health is at least stabilized.
If the check fails, the character continues to lose hit points at the normal rate for a critically wounded individual. If the first check fails, the healer can try again each round until the patient is either stabilized or dies, A critical fumble on the use of Healing will kill the patient whose hit point total is still negative.
Once the patient's condition has been stabilized, the healer must make one successful Healing skill check for every hit point below zero. Thus, a healer would have to roll three times if the patient's hit points are at -3. If all the checks are made, then the character's health is stabilized at zero and will live. Failed checks inflict one point of damage on the wounded character, and a critical fumble still kills the patient. As is evident, curing a patient in this condition is a long shot at best.
When determining the chance of scarring, the system shock save is penalized by one point for every two negative hit points the character had at the lowest health level. If the damage came from cutting/impaling sources, the character must also make a successful Body-Mind-Spirit or contract an infection from the wounds. For internal injuries (like those caused by a club or a staff), the character must make a system shock save at +6 or lose one point of Constitution permanently as a result of blood clotting.