Rebekah Stewart, a nurse at the US Public Health Service, got a call last April that brought her to tears. She had been selected for deployment to the Trump administration’s new immigration detention operation at Guantánamo Bay, Cuba. This posting combined Donald Trump’s longtime passion to use the offshore base to move “some bad dudes” out of the United States with a promise made shortly after his inauguration to hold thousands of noncitizens there. The naval base is known for the torture and inhumane treatment of men suspected of terrorism in the wake of 9/11. “Deployments are typically not something you can say no to,” Stewart said. She pleaded with the coordinating office, which found another nurse to go in her place. Other public health officers, who worked at Guantánamo in the past year, described conditions there for the detainees, some of whom first learned they were in Cuba from the nurses and doctors sent to care for them. They treated immigrants detained in a dark prison called Camp 6, where no sunlight filters in, …