Interesting article. As someone who has worked in tall buildings for some years, I strongly disagree with the notion that people act out of "fear" when they are in close proximity to others like this.
I think the single biggest reason why people act disinterested and detached in an elevator is that we don't like being in close proximity to others unless it is on "our own terms." In other words, we act the same way in an elevator that we do while walking down a corridor in a shopping mall. We ignore the people around us and pretend they don't exist because we simply don't know them . . . and their presence has nothing to do with what we're shopping for.
For some evidence of this, just get on an elevator in a building where one tenant occupies the entire building. People will usually act much different in this kind of situation. Even if they get on an elevator with someone they don't know, they're far more likely to engage them in random conversation during the elevator ride -- because they know up front that they have something in common.
Ah, but if you are situationally aware you DON'T do this.
You PAY attention to the people around you.Being situationally aware has kept me out of some tight spots.
I learned the technique, and it is a learned behaviour, from a Cheif Petty Officer in the US Navy while I was stationed in South East Asia.