Following Signage

We take the metro for 1 Egyptian Pound (app. 20 U.S. cents) to our Arabic school. We are shoved backwards by a crowd of sweaty men exiting the train as we try to elbow our way in and one of them yells at us something like "rung duur!" I think to myself that this is worse than getting on at Grand Central in rush hour -- lawyers and investment bankers are never this rude -- before I see that each door is marked as an entrance or an exit with bright red and green paint. I realize then that "rung duur" probably meant "wrong door"....