Previously, Trump had called DACA recipients “incredible kids” and said they should “rest easy.”

“It's yes, then no, then yes, then no,” said Denisse Rojas, the first undocumented student to attend the Icahn School of Medicine at Mount Sinai in New York. The extreme uncertainty, she said, “shows how little regard they have for our day-to-day lives.” DACA is “tied to so many opportunities, to take it away with a stroke of a pen is heartbreaking,” said Rojas.

Without DACA, there is no clear path for these students to complete their training, repay their loans, or practice medicine. For medical students committed to a decades-long career path with mortgage-sized student loans, the uncertainty makes it almost impossible for even type-A overachievers to plan for the future. “I don't think I’ve thought about what I would do instead,” said Latthivongskorn.

I reached Marina Di Bartolo, an internal-medicine doctor at the University of Pennsylvania, on her walk home from the clinic on Thursday. That day, she treated a patient with high blood pressure, another who needed cataract surgery, and someone with a herniated disc from bungee jumping gone wrong. “Not the most glamorous stuff,” she said.

Di Bartolo’s parents brought her from Venezuela at age 7, then overstayed their tourist visas. Her mother works as a babysitter and housekeeper, and her father does odd jobs and construction. “Right now there is no path to legalization,” Di Bartolo explained this winter. She said the only alternative she sees is “doing what my parents do.”

“The day it is revoked, I have to take off my white coat,” she said.

Meanwhile, the United States faces a shortage of up to 104,900 physicians, according to the Association of American Medical Colleges.

Di Bartolo won a full scholarship to the Yale School of Medicine, and to Princeton before that. But for students who rely on financial aid, the end of DACA would mean they can no longer afford school for a simple reason: Few banks are eager to lend to students legally prohibited from working after graduation.

“I won’t be able to pay my living expenses, much less my tuition” without loans, said Cesar Montolongo, a professorial MD-Ph.D. student at Loyola-Stritch School of Medicine in Chicago. Montolongo spends his days in a brightly lit lab researching the root causes of urinary tract infections. “It’s bittersweet to have found something you’re happy doing, knowing it might be taken away,” he said.

Sunny Nakae, the dean of admissions at Loyola-Stritch, said students face “a huge chasm of uncertainty.” Loyola was the first school to actively recruit undocumented students, and has admitted about 30. But even though DACA has been under threat since President Trump’s election, Nakae said she has received more applications from undocumented students this year than ever before. “Undeterred might be too bold a word,” said Nakae, “but their choices are to put their lives on hold, or to keep moving forward.”