It makes sense that 10 or 20,000 years ago, human beings would retreat to find the high ground. It was good in the Middle Ages and in the last couple of wars to control the high ground. With bombs and airplanes, the importance has lessened, but it is still a good idea – if you are out in the open – to take the ground just beyond the highest ground, especially if you have a gun.
However, we have all seen enough movies to know that going up the stairs is the wrong move every time. Are you going to hide in the closet or under the bed? Are you going to jump from a window? In the movies, you are most likely to die even if you get to do any of those things. If you are facing one individual, get outside and get some help.
It might be okay to go to the top of the stairs if you have a plan to hold them and help on the way. Kicking someone down the stairs is a great idea, and if you have more than one attacker, a narrow stairway will keep them from ganging up on you.
Movies are written to be suspenseful, and running outside, telling the truth to the police and not allowing the attacker to get close to you by running into a dead end would make for short films that seem to have no point.
Still, if we are willing to accept that someone choosing to run upstairs instead of to ground level is viable, maybe it as something to do with the primal core inside each of us.
Would that make tripping in the woods instinctual, too?