Get Caught Watching The Paint Dry Day!
You'll have to do it at rush hour, so you should make sure and stand out. Go to the girder with the "Wet Paint, Do Not Stare" sign on it and stand right in front of it while you wait for the train. When the train comes, just stay right where you are while everyone is piling on. Some of the passengers pressed up against the windows are bound to see you staring at the freshly painted girder, and they'll be sure to rat you out to a Marshall on the train car.
The Marshall will pull the signal for the conductor to open the doors again. The Marshall will step out onto the platform and approach you. The train car will close up and pull away. Everyone's eyes will catch you as they pass, and you'll just know those cars are silent as the grave inside. Once the train has completely left the station, the Marshall will point his gun at the side of your head so that when he shoots he won't splatter any blood on the wet paint. Then he'll phone his dispatcher to report that he caught another one.
Your body will lay uncovered until three train cars pass. Commuters will step around you, averting their eyes away from girders bearing signs.
Happy Get Caught Watching The Paint Dry Day!