Start at the entrance of the stadium (where the parked trucks are located, and where you get into the contest. From there, look at the tape. You should see it above the glass dome behind the subway-like spline entrance. Go down left from here and wait for a vehicle to drive out of the tunnel. Skitch it towards where you started from. Make sure you are on the left side of the car. When you are about to pass the subway entrance spline, get of the vehicle and spline the entrance from the side. This will launch you across the dome into the secret tape.