Actually, yesterday afternoon, Zachary wasn't just sitting idly on top of the Black Car, but was using the Art of Controlling Objects to manipulate some things. Within the range of his Divine Sense, he found a Giant Scorpion and personally tested its combat abilities.
After multiple tests, it was confirmed that the attack of the Giant Scorpion couldn't break through the Black Car's defense, and he had said as much to his mother only because Robinson William's wife was nearby. Zachary wanted to avoid any hassle, which is why he had specifically said that.
The truth was as long as Father Dong and Mother Dong were on the Black Car, Zachary could ensure their safety to the greatest extent.
Since the Black Car was Zachary's Magic Artifact, even if he was not at the campsite, as long as the Black Car was within the range of his Divine Sense, Zachary could control it at any time and from anywhere, even teleporting the Black Car directly into the Cave.
