Dr. Katrina A. Armstrong was out of sorts.

It was April 15, 2013, her first day as the physician in chief of Massachusetts General Hospital, and she was grappling with the enormity of her new job. She felt, she mused later, as if she had moved abroad.

Then two bombs exploded near the finish line of the Boston Marathon. Mass General prepared its emergency room as 127 of the wounded headed for the city’s top-level trauma centers, part of a response that ultimately earned Boston’s hospitals sweeping praise.

Dr. Armstrong, who was abruptly appointed as Columbia University’s interim president on Wednesday, has often talked about the aftermath of the terrorist attack on Boylston Street.

“We had had, and continue to have, this opportunity to be part of the healing that I think almost no other group got to do,” she said in a Mass General podcast in 2018. “And so to be able to heal both patients and a community that way, it was an incredible time to start.”

Now Dr. Armstrong is tasked with leading another community through the aftermath of a different kind of trauma, as Columbia grapples with the consequences of protests, accusations of antisemitism, an unwelcome turn in the global spotlight, and now the resignation of its president, Nemat Shafik.