If one considers violence, in itself, to be unethical, or at least undesirable, then minimizing the time one, or any other, is exposed to violence would be paramount to the reduction of harm from exposure to said violence. Therefore, achieving a state of maximum efficiency with violence could be considered the best way to reduce the amount of violence anyone is exposed to, and thereby reducing the harm associated with violence. An ability to achieve a violent outcome, when required, as painlessly and rapidly as possible would be the ultimate goal.
Example:
A) One is attacked in an alley, and having no previous training or weapons with which to defend oneself, one is subject to the will and whims of ones attacker. However long, or painful the attacker wants thing to go, that is what the victim must endure. Wallet theft, rape, murder, whatever the attacker wants, the attacker gets, within whatever parameters they elect to pursue. The victim relies on the goodness of their fellow man for protection.
B) One is attacked in the same alley, same attacker, however, the victim is packing a knife and knows how to use it. After two minutes the attacker is dead, the victim, bleeding, goes to the hospital for minor stiches. One is more reliant on the self to defend against fellow man.
C) Same alley, same attacker. The person attacked is highly trained in highly efficient use of violence. Within seconds the attacker is incapacitated (dead or unconscious) and the victim of the attack carries on along their previous path, having barely broken a sweat.
Option A has the largest, longest violence and the most suffering for the victim, and potentially for the attacker, on the premise that violence harms in both directions. Option B) has the next highest level of violence, as violence occurs to both parties and the event lasts longer than it needs to. Option C has the least violence involved, both in duration of time and energy expended committing violence, therefore Option C is the most ethical position.
Violence should not be one's opening option, however, once it is there, one should be fully conversant with it and use it as efficiently as possible, minimizing suffering.