"you are under arrest!"

This morning at a minibus terminal in Lagos, a policeman came up to me and yelled at me sternly "you are under arrest!" I froze for 2 seconds and the notoriously brutal and corrupt images of the Nigerian policemen and soldiers took hold of my mind. I didn't feel scared by him and decided to be cool and just play along, I said with a big smile "oh, reeeeeeeally?" Then he laughed, too. It turned out that he was just trying to mock me. And I was a little amused.