[The word "demon" doesn't have much effect on Boone. He just watches Belloq carefully move a couple of tiles, then looks over at Tuco. He looks terrified, but Boone can't understand his fear. He doesn't believe in demons. He looks back at the puzzle, reaches up to move another tile, and waits.]

...Think if something bad was gonna happen, it would've happened by now. Maybe as soon as we started messing with it.

[He actually has no idea if that's how it would work, but he's trying to make Tuco feel better.]