Asymptotic analysis

"The most striking thing to him about the tape is that it includes split-screen footage from three other elevators, on which you can see men intermittently performing maintenance work. Apparently, they never wondered about the one he was in. (Eight McGraw-Hill security guards came and went while he was stranded there; nobody seems to have noticed him on the monitor.)"

http://www.newyorker.com/online/video/2008/04/21/080421_elevators