Relevant and Irrelevant Data

If you have a good plan, you don't change the plan without new, relevant data.There's a pyramid that precedes this: if you've never created and executed a plan before, you wouldn't necessarily recognize either a good plan or a terrible plan.  If you've spent no time analyzing the situation (both specific, e.g. "what is happening right now?" and general e.g. "How do these things usually develop?") your plan is basically random hope.
So to even get to what we are talking about, you must know the problem, you must be able to design a plan, you have to be able to integrate a wide variety of sources and information, you have to understand your own resources and the mechanics of the situation...and on top of that you'd better not be stupid.
With all that, and intelligence, you'll make a good plan.  Execute the plan, without hesitation.  Stick to the plan, even though some things change... until you get new, relevant, information.
Steve writes on the last post that given the dynamic of a close range knife assault, "I'm curious as to why expecting to get cut or stabbed *isn'*t part of the scenario? "
This is an aside, not to the meat of the post:  Some instructors will tell you you will get cut in a knife fight or knife defense.  Some will tell you to trust the technique and you won't.  Both are lying through their teeth.  They may not know it, but here's the deal: sometimes you get cut, sometimes you don't.  I'm standing at five (two close range assaults, one attempted draw, one free weapon brandishing, one unarmed disarming with a team) without a scratch.  Sean at six without a scratch.  Brad had one, with literally minor scratches.  Don't know how many Mauricio has had, but some were messy bloody.You don't know if you'll be cut.  You don't know if you won't.  You don't know if the angel of unbelievable luck will be on your shoulder or the bad guy's...and neither does your instructor.  I despise when people say either thing (will get cut or won't) for purely practical reasons.  Assuming you say it outside of a group of martial ballerinas, it may be tested someday.  If the student gets the opposite result he or she will have to wonder: "What else did the instructor lie about?"Making absolute statements in a situation with absolute stakes... you'd better be right.  Because if you are blowing smoke out your ass about this, you are blowing smoke on other things, too.  Maybe on everything.  But it doesn't matter, because the student cannot and should not ever trust you again.
What about, "Expect to get cut?"  here's where we move towards the meat of the post.  In any other endeavor, is focusing on an expectation, especially a negative outcome, considered an intelligent thing to do?  You shouldn't be surprised if you get cut (or don't) or if you get punched or slammed.  But wasting energy or thought expecting anything is stupid.  You can't afford the inefficiency.
This might be a hard sell but (especially for Steve and other authors out there, this is one of the ways operators think that civilians don't get): Getting shot or stabbed isn't automatically a relevant data point.
If you made a good plan, say to run away as fast as you can, and you get shot... does that affect the plan in any way?  If running is the right thing to do, running while bleeding is probably even more important.  Standing still and coming up with another plan is suicidal.  Covering the distance you just made under fire to fight while wounded is stone dumb.  Trying to hide when someone has you in his sights is about as effective as hiding under the covers.
Getting shot is not automatically a relevant datapoint.  Your leg buckling is.  Getting stabbed is not.  Everything getting slippery or your eyes starting to go black on the edges are.  Pain is not important to the execution of your plan.  Loss of limb function is.
And so with close range knife defense: if you have no option but to fight, does getting cut or stabbed change that fact?  Is it now time to stop and think?  Or to expose your back and run, which is not easy nor safe at knife range.  It should, at most, be a signal to increase the ferocity, but if it is, you weren't being ferocious enough to begin with.