I'm with Kentbob,
I thought it looked silly. Like Hock just mentioned, this situation is happening in an environment, and people are moving and thinking, and possibly fighting. The knifer can defeat any attempt by taking a few steps backward. In fact, in a type of choke, using the knife, the knifer is really in a position of the kill. What I didn't like the most is when he turned his head to get the knife to fully cross his throat. Maybe not such a good idea. I think a better solution is to (and this is if you are going to escape at this exact moment) that the knifer's elbow is sticking way out, there is room between the elbow and the victims neck. It goes like this:
1. left hand on knife or hand of attacker.
2. right hand slaps elbow inward.
3. turn to the left, duck, continue turning, now you are almost facing attacker, and the knife has grazed maybe your ear or hair, but now the knife is between you and him, and we wind up at the "in the clutches of" module.
4. troubleshoot from there, and fight on.
Mr. Barnett