Voiceless, what do you think of the following scenarios:
1) Standing in front of a knife guy, pushing yourself off of him (chest), take a big step (3 ft) and face opposite direction, running moderately and controlled. If he tries to run after you and you have created enough distance, you will simply elephant-stomp him in the stomach (small elephants are known to give sort of a backwards kick and it can be deadly). In other words, a straight backwards kick. Why this approach? Well, our sensei has developed this new method. He says "this way, the attacker can't get close enough to me. He can't grab me because my leg will be kicking him and he will cripple to the floor from the kick. He would have to get close enough to be able to grab me, but he can't, because my leg is protecting me with the backwards kick." This approach worked for one of our club members who got ran after by a drunk guy. He kicked him in the stomach with the backward kick and they had to carry the guy away back to the bar. Of course this works for a drunk, fighting-ignorant guy, but for a vicious trained maniac.. I doubt it. This is why our sensei and us are always open to opinions from the outside. Do you think this would be a good approach? My opinion is that there might be a problem with the guy cutting one of your leg arteries.. I don't know.
2) You are standing in front of the knife attacker and just all of a sudden, you run backwards, but with fast great steps, still facing him. After those steps you run the hell away. Supposedly the attacker would be that dumb that he would be surprised for that second that you take steps back. He would be like "huh?" in his mind and that would supposedly be enough for you to get the hell away.
So, let me know what you think about these approaches.