My Auntie used to be a cruise ship doctor. Like you say it's a sweet gig and got to take her husband too. She didn't have anything like this happen but it can be, like any job, crazy busy and crazy slow.
I think she told me one time there was signs of an outbreak so people were confined to their rooms and precaution like using tissues to open doors then dispose of instantly afterwards. I guess the tactic there is preventive. Nothing severe happened that I know of.