If I were being chased by a guy with a knife...

You've heard this expression.  If you are a runner talking to a non-runner, casually mentioning how many miles you ran today, the non-runner chimes in and says, "I couldn't run that far if I were being chased by a guy with a knife!".  Similarly, if you are a non-runner trying to flatter or otherwise appear less immortal than the runner, you respond to the runner's mileage tally with, "I couldn't run that far if I were being chased by a guy with a knife!".  It is the most overused and least logical expression ever shared between the worlds of runners and non-runners.  No wonder we don't understand each other!  


Why is it always a knife?  And a guy?  Why not a bear?  Or a guy with a tarantula? Or a bear with a tarantula?


Here's the scenario. I ran 9 miles.  Someone "couldn't run 9 miles if they were being chased by a guy with a knife".  Why would a guy run after you for 9 miles with a knife?  What the hell did you do to this guy that he felt compelled to run 9 miles to stab you?  Where are you that there isn't anyone to call or anywhere to hide from this 9-mile-knife-wielding houligan?


Okay so let's just go along with the scenario.  So there I was, mugging someone, and the victim turned on me with a knife and... No, that's not realistic.  So there I was, kicking someone's puppy, and... No, wouldn't happen.  So there I was, insulting someone for having obnoxious, ill-mannered children...yeahhhh that's more like it... and the parent of the ill-mannered child comes at me with a knife.  In a fit of rage the parent, let's call it a father, abandons the child and a pursuit ensues.  (I think we now understand why the child is so obnoxious, and that my insulting tirade was completely justified).  In my fantasy I'm going to pretend that I happened to be wearing running clothes.  I spin and take flight, and in a burst of adrenaline I take off at a fast clip, but I hear this maniac behind me and he's too close for comfort.  My speed increases, until my years of training start creeping into my psyche.  I can't sustain this pace.  If I start off too fast I am going to bonk.  I'm not adequately hydrated.  I should start off slow so I can achieve a negative split.  All of these educated running thoughts are going to overwhelm me and supersede my fight-or-flight instinct.  No doubt I'll try to rationalize this with the maniac so he can understand the need to Finish Strong! but it's a safe bet he'll stab me before I can show him my split times on the Garmin.  So in this scenario, it's not going take the stabber 9 miles to reach me.  He'll get to me before we reach the street.


Now, let's just say I make it to the street, and he has to pause for oncoming traffic.  I get a slight advantage, and from there I have time to fully prepare my race strategy.  And, there are no side streets or payphones for the next 9 miles.  In that case?  Oh yeah, I got that.  And later the local news would tell of a mysterious John Doe found on a deserted street, knife in hand, cause of death likely cardiac arrest, heat stroke, dehydration, or feelings of inadequacy.  


Is this one of the subconscious reasons why we run distance?  To have a sense of immortality, where we possess the ability to flee from danger?  What if, instead of thinking of whatever horror we are running from, we think of the fulfillment that we are running towards?  What would you run 9 miles for?  Or 13.1? Or 26.2? Or 50????