Here's my suggestion; worked for me.
After I unscrewed the screw, I couldn't 'pop' the door out to it's rather snug fit. So I got the most harmless thing I could find that wouldn't scratch anything: a rather dull toothpick. I inserted the end into one of the 'vent holes', applied a tiny amount of leverage, and POP it came right out. Nothing worse for the wear.
I'd wish you good luck, but you really don't need it. It's SUPER easy.