When Zuko tests the hanger up and puts his hand on it, the hanger moves forward a few inches, pulling from him, and at the same time the color in the levers changes slightly, getting dimmer, turning into a strange, indescribable mixture. Upon testing them, the screens slide a bit before returning to the original point, snapping back into place with a loud click.

It seems merely grabbing the hanger up in the zipline won't be enough to enable the levers, but they're on the right track, that much is clear.

Careful, though -- like Bradley wondered before, it doesn't seem there's any place for a new hanger to appear. Only one passenger and one try!