I also cannot stop asking that same question ...
A very long article basically elaborating your answer.
https://www.nytimes.com/2020/02/22/world/asia/coronavirus-japan-cruise-ship.html?referringSource=articleShare&fbclid=IwAR0hY0FRj9RHTK218-Ji8WFDBcX_fz0B-7PNQuZkZdJg5Jf_L-lpm5N4Tz0
Highlights:
* The
delay by the Japanese government, along with slapdash and
ineffective containment measures during the two-week isolation period, would help turn the Diamond Princess into a floating epidemiological disaster.
*
Feverish passengers were left in their rooms for days without being tested for the virus. Health officials and even some medical professionals worked on board without full protective gear.
* More than 1,000 crew members shared close quarters below deck. Many were infected. Through it all, crew members were working overtime, sometimes as long as 13-hour shifts. The crew members, who numbered 1,045, had to remain on the job even as they faced the greatest risk of infection.
All told, 85 crew members have tested positive for the virus. Below deck, they shared close quarters, with as many as four to a bathroom. They ate their own meals buffet-style.
Looking at this photo, I wonder if the medical personnels changed their PPE from one room to the next.
Copyright: Cheryl and Paul Molesky, via Associated Press