David’s face is so mortified that Balthier is tempted to lie to him.

“I’m afraid I promised you honesty. That’s the end of it though. Oh you did fall off a bench.

I have my bike. You want to go after him?”

Honestly Balthier wants that infuriating child off the streets. And he can probably create a good enough decoy for David to capture him. That said he does not want to get caught in another of Filter’s effects. But he doesn’t want other people getting stuck in them either.