One punch is capable of ending a life. AND

A mature adult can typically discern between a genuine life or death threat or a lower grade threat requiring a lower grade response, such as the bodybuilder and the geriatric. AND

Technology is how we create 'equality' with regards to interpersonal violence. Technology is not yet advanced enough to create a phaser set to stun. Less lethal alternatives to firearms do not give the same kind of power to a small bodied or disabled individual that a real gun in the appropriate caliber does.

Until a device is invented and popularized that accomplishes the same thing as a pistol in the right caliber without killing the attacker, this is the reality we face. No gun, this woman is dead on the pavement and this guys life such as it was is over. This is the worse of the two options because an innocent, non-aggressive person is dead.

If you see some third outcome when a large person with more muscle attacks a smaller person with less muscle who has not offered them violence, please, share it.