I have never been in a knife fight, I have defended against an edged weapon on three occasions. I never got cut but chalk it up to more luck than skill and I will always take luck over skill:)
What I teach is from experience and expertise is the most likely things I believe you will be able to pull off in the positions you are likely to end up in, not the ones you would like to be in.
The anatomical truth is that a hammer fist with the pommel of a knife will stop someone faster than a stab to the heart even though the stab is more likely to eventually result in eventual death.
I like to watch UFC but here are my thoughts on how it does not apply to the street-
Concrete does not give like the mat.
In the street you do not have a cage separating you from the bad guys friends.
In the UFC their is no danger or even anxiety about multiple opponents or weapons.
Even if you are knocked out and your attacker wants to keep damaging you their is someone in the octagon to protect you.
Everything you are not allowed to do in the UFC are the first things you should do in real life.- George