Port Royal 2 Update Kingdom Hearts 2: Port Royal?

Kingdom Hearts 2: Port Royal? - port royal 2 update

I'm on my second time, when I returned to Port Royal, with 4 sends the Nobodies steal Luxord 4 medallions from the chest.
When I left the boat to retrieve the 4 medallions and landed in the first box, I missed the first (I had no time because they knew where it does not). Then I heard from the tutorial it does not matter if he loses or not, because if you always back and forth in Shipgrave the person shown on a random basis. I had 3 medals, but after I come and go, the fight against the undead pirates, about 10 minutes, and no group ...

Was it a mistake to have lost the first one? Because if I did not have the 4 medallions! I tried to go in a different world at the time, but no show.