This is a classic example of "RPG time", which is what happens when characters have detailed discussions of things that take fractions of a second to occur in the reality of the game world. The classic example is players stopping to have extended discourses on their group combat tactics in the middle of a fight scene, when if the fight was really happening, they'd have had their asses kicked before they could even open their mouths.

Here we see Qui-Gon hold such a discussion in the last fraction of a second of Watto's chance cube roll, late enough so that he can see which side it's going to land on, but with enough time to spare so that he can subtly and unnoticeably use an ability to change it.

Transcript

GM: You can't reroll Watto's die. That was in-game.
Qui-Gon: You used a d6 to determine the outcome. I'm rerolling that one.
GM: And you think Watto's simply going to let you pick up the die and try again?
Qui-Gon: I cast the spell in some subtle way to make it keep bouncing.
GM: <sigh> Fine.
Watto: If you can manipulate the race the way that die just rolled...
Watto: ...You may just have a chance.
Qui-Gon: Yes! The race is tomorrow, right?
Watto: It starts in half an hour.
Qui-Gon: Oh.
Qui-Gon: By the way... If the kid wins the race, you have to give Shmi her freedom.
Watto: Is this another bet? What are you staking?
Obi-Wan: Not us! Not us!
Qui-Gon: Queen Armadillo of Naboo.
Obi-Wan: Oh, good grief.
Watto: You're on!
R2-D2: {aside, to Obi-Wan} Didn't you take off without us?
Obi-Wan: {aside, to R2-D2} The Queen wouldn't let me. Something about leaving her handmaiden behind...