At the second to the lowest level of the airport face the center quater pipe. Directly left of the quarter pipe is a red pole that sticks out and grinds to the right alongside the window. Grind that pole then ollie to the next pole. Right when you start to grind the second pole wallride the glass into the gate. If you time it right to where you land in the middle of the gate and go outside.
When outside you can use the Flying Glitch and maybe even land a 1.1 BILLION point score like shown in the last picture!
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