When Zenon and Dasha are coming back from having the scary encounter with Selena, Zenon drops her zap pad. It falls about the speed it would on Earth, however since the moon's gravitational pull is less, it would have fallen drastically more slowly. Notice how long it took Zenon and Dasha to fall and I'm guessing that they weigh about 105 pounds and 80 pounds (respectively). An object that had a lighter weight would have fallen more slowly. Drop a five pound weight and then drop a feather, which one takes longer to hit? Even if the Moon is in a vacuum. The zap pad would have taken longer to hit the moon's surface because the weight had been reduced coming from the Earth to the Moon and it wouldn't fall at the same speed on the Moon as it would have on Earth. [While you are right in that it would fall slower on the moon as evidenced by the astronaut landing. Galileo proved that by dropping different weights off the Leaning Tower of Pisa that different weights do fall at the same speed making gravity a constant which debunked the beliefs of Aristotle. Zenon, Dasha and the zap pad should all fall at the same speed.]