Geoffrey Wiseman: I do see what you mean about the conundrum of multiple elevators. Let's confine this case to two-story buildings, though, which typically (though not always) have only one elevator.

I don't think there should be a button to call the elevator in the first place – I think standing in front of the elevator should suffice (a sensor similar to those used in automatic doors would work well, though it'd need to be altered slightly, so as not to call the elevator every time a person walked past it). A simple light system representing the elevator's current location and transit would be great feedback, as well.

As for opening the doors if you've missed the window of opportunity to exit, simply pressing the doors while the elevator is stopped would be the most obvious solution to me, and much preferable to a button that's not even on the door. As elevators operate now, you can pry the doors open with a bit of effort even when the elevator is in motion, causing the elevator to stop (I enjoyed doing this in malls as a rebellious teenager). But having a "push area" on the door (similar to the rubber strip you push on the back door of a bus to open it, though ideally less ugly) seems much more obvious and direct than a button you have to search for amongst several.

And while you're right that this isn't the ideal place for this discussion, it's nevertheless an interesting one.