Maybe I am extremely naive or something but I usually don't feel any sort of fear or need to be behind people in elevators for protection reasons, it doesn't seem very common for people to go on shooting or stabbing rampages in elevators, it also seems like a very illogical place to try to do anything. I've never been groped, etc. on a elevator either (though I know of people who have been raped in enclosed staircases, never elevators though).
I do usually take the stairs, even if I am pretty far up, unless I am carrying a bunch of crap or pushing a cart, etc. just for the exercise, not because I don't like people.