Two weeks was picked as the quarantine time because that's supposed to be the maximum amount of time between exposure and symptoms appearing if the exposed person has caught it. But since more and more people are catching it, that quarantine should be expanded to two weeks after the last case seen.
The two weeks might be different if they are doing regular testing on everyone to see if they have the disease instead of relying on symptom appearance.
But the rest of the passengers better not be getting off the boat in one more week. I doubt they are keeping total isolation, including individualized HVAC, to prevent passengers from infecting each other.
They do reset the quarantine clock with each new infection. As of today, they have to sweat it out for another 14 days, and on and on that goes. Depressing....
Any sane quarantine would involve getting them off the boat and into small groups. This approaches mass-murder.