I have spent some time this weekend thinking about this very same video and how it might actually be done. I say actually because this video is fake. But, I would like to see it used in a haunt so I drew out some "4-sided triangle" ideas inspired by Escher. If I come up with something practical enough for haunts I will post it here.
My first and only thought...FAKE! Haha
That's my alma mater. I have walked those stairs many times. Great video and concept.
I found a couple ways this could be done for coherent circumstances. For example, the following could be done for video using a stationary camera.
You could airbrush steps on a smith flat surface. On one side you only paint the tops of stairs. The other side you paint both tops and base boards.
I have another solution that I need to draw out and post tomorrow.
I drew out some plans to make this seem like a haunter could use it in an attraction, but the only way I can see it working is if the people watched and not participated. So, if you were to walk up the stairs turn a corner in front of a group of spectators then continue up the stairs. Once you turned the corner you would appear coming up from the bottom again. Similar to the video but done live.
In the two pictures I took of a stairwell, I stood just to the left and to the right specifically to show you how this might work. The center wall is about the thickness of a 2x4, so a little less than 5 inches (adding drywall). You mind assumes that the back of this wall is also at 5 inches. But, the back could exist at 3 feet wide (if necessary). Since no spectator walks the steps the back won’t be seen.
Everyone watching would be able to see the back thickness only if they were to stand directly in front. If the people were to be in motion, walking from left to right behind a rope (like an exhibit), the illusion might not be as noticeable. And a smart builder would "carelessly” install a support pole in the center so people’s views would be slightly obstructed.
Hiding the back thickness of the wall is only part of the battle here. The second part is how did that guy get from the top of the stairs to the bottom so fast? Well in this idea, I dropped him down. At the top of the stairs just behind the wall is a lift. Counterweighted, a man standing upright, could drop straight down, hidden from view, and come walking out at the bottom. The lift would go back up by itself to reset.
Now, I am not saying in any way this is how it was done. In fact, I will say that it wasn’t done like this in the video. Remember, the video is fake. But, if there is an idea, sooner or later…one way or another, someone will figure a way to do it.
In each case they used twins that were dressed and timed out. No camera trickery and that is how you do it in the real world and fake out authentic participants!
In haunted houses you have several identical costumes and the same guy is in dozens of places there to scare you again. Or how did he get from here to there so quick? A serious number of magic tricks are done like this and sometimes the entire family and a dog are identical twins acting and doing impossible things like coming out of an elevator when you just saw them behind another place. Even some magicians have crazy signature looks and hair so a double can easily be made to look like they came through a wall only they never really moved or came out of nowhere, actor #2 appears.
So all these guys are doing is authentically freaking out a few students, filming it and coming up with lots of web prescence to make it into an urban myth.