They had met at the spaceport to agree on the scheme, but entered the casino separately. The Wraith was supposed to control the game, so she had taken the 'special' dice the Colonel had. The trick was just to slip the unto the game.
Eventually, they joined a sabacc table where Corellian Spike was played, as separate players.
[Hala contributes 272, Motr contributes 228]
The game went smoothly.
EA8. Gambling (Tier 2). Cheating (Deception). Hala's Dice & Assistance. Influence. Mask.:
2eP+1eA+3eB+1eF+1eC+2eD 4 successes, 2 advantage, 2 Light Side[Dark Pip for additional Advantage, +30% to bets]
[Hala nets 272 + 82 = 354; Moyr nets 228 + 68 = 296]