Unless someone has "seen the Elephant" I think it a little unrealistic (if not delusional) that they can whimsically state that they feel confident they can survive the melee with a mere five or six shots that they really "feel" that they can deliver with Camp Perry precision in said circumstances.
Far better to error on the side of caution and assume the worst as truth be known most people are lucky to hit a bus at ten yards under duress, let alone a moving and unpredictable assailant at night in a strange location.