I heard everything you said

This is another funny little story that happened on my 2002 trip to China. The last leg of our trip took us to Beijing. I got in the elevator with a couple of students to go to the lobby. There were was a twenty something looking Chinese couple already in the elevator when we entered. They didn't say or do anything too indiscreet but I noticed them start to look over at us and saying things in Chinese. I couldn't hear everything but I picked up words that let me know they were talking about us. When we got to the bottom, just before the doors opened I said "Wo ting dao ni swo da hua chwen bu." Translation: "I heard everything you said." When I said that, their eyes widened and their jaws dropped in utter surprise and shock. They rushed out of the elevator as fast as they could, never to be seen or heard of again. At least not by us.