Need help "forcing" a colorful event to make my players choose a color (and then gift them dices of that color). First time DM with first time players

I bought a cheap pack (8 bags of 8 different colors, with the classic dices each d6/d12/d20 etc...) to gift them to my players in our first session, but I'm having trouble forcing the players to choose a color with a logical in-game explanation.

The session will consist in a one-shot where the players are prisoners in a ship and must take control of it somehow (by creating a revolution with other prisoners, befriendig guards etc...), then gide the ship to safety while maintaining order with the other prisoners (lack of food, tensions between races etc...), some merchant/pirate ships, storms and a kraken as a final boss.

If I can i will end with the classic all fade to black and wake up in a beach in the next session (so the characters of people who don't come back have a reason to not being there, or even finding them later on).

I was thinking that maybe the capitan forces to fight some random prisoners for fun/teach a lesson and makes teams (so I would use this to introduce combat rules in a semi tutorial for them)

Later on it would be easy if I can get to the merchant ship (he only has on bottle of dye of each color, but that whould mean that we have played until then with only a single set of dice (mine).