Likewise if the Wizard was privy to Luka's own private thoughts, they'd remind him that they only met him a handful of minutes previously and he was claiming to be a time traveler. On the list of "bad lies" that was pretty high up there.

But he keeps adding more weight to the "maybe it's true" side of the scale. He's cast enough doubt on the situation that now they're considering it as a whole.

"They were going to destroy the planet." They choose to answer, bringing the focus of the entire situation back to the one thing they know as entirely factual in this moment. All the others could be lies, so they'd go with the truth for now.

"Which would have hurt, and killed, you, and all others. Did you know of this?"