Dr. Ahmed Ali, the chief of radiation oncology, works on the first floor of the Northside Hospital Midtown medical center. Ali said he was on his lunch break and had just reentered the building when he saw a swarm of police officers, armed with assault-style rifles, enter.

He said he talked to a security guard who told him there had been shots fired on the 11th floor. According to Ali, the security guard also told him that police had been called after an elevator door opened, revealing a pool of blood inside. After he evacuated the building, Ali went to the corner of Spring and 14th streets, which is his team’s meeting place for fire drills.

”A lot of my colleagues are still in there,” he said.

Another doctor, Timothy Simon, a colorectal surgeon who works on the 12th floor, said he was in the middle of a surgery when he heard shouting. He was able to finish the surgery before security escorted him outside. He said he was told the shooting was in a medical office on the 11th floor.

Simon said the confusion in the area meant he couldn’t get to his car.

”I’ve called my wife to come get me,” he said.