Let's face it, if someone merely slaps you on the cheek, you are not really being mortally assaulted, you a merely being insulted and humiliated in public.
Christ did not say if someone comes at you with a knife, let him kill you.Turning the other cheek means do not return insult for insult, or humiliation for humiliation.
It really has NOTHING to do with a violent physical attack.
Exactly.
A slap on the cheek is not a threat to your life. However, responding in kind can cause the situation to escalate until it becomes a serious threat. It is better to endure the insult and let your opponent cool down.
"A soft answer turneth away wrath: but grievous words stir up anger." (Proverbs 15:1)