"It's kind of like that instinct, that motherly instinct," he recalled. "I immediately ran into my office, grabbed the emergency handheld radio, and heard the Force Protection Agency's call for 100% evacuation," he said.
"I immediately went to our command suite and advised them to evacuate, but we still didn't have any idea of what was going on."
As they left the building, everything "was just basically smoking." They later learned what had happened from the news broadcasting outside.
But rather than evacuating for his own safety, Pagdanganan and his colleagues, who did not sustain physical injuries, helped evacuate patients who were in the building "to get them outside, to the north parking lot."
"We established multiple teams to go inside the Pentagon, because we started seeing casualties," he said. "Your instinct is to basically jump in and take action right away, not thinking about calling someone else or calling your family."
"With my colleague, we ran into the center courtyard, Ground Zero, where we helped set up a triage area, along with the Arlington County Fire Department and Police and the Pentagon's Emergency Operations Center," he said.
But another call on the radio mandated for 100% evacuation: "Everyone must leave the building now," he remembers it saying. "We had to evacuate then because we heard there was another plane coming towards us," he said.
"My life changed that day," says Pagdanganan. "I didn't get to talk to my family for almost nine hours - they had no idea what was going on with me - and when they finally saw me, they thought they were seeing a ghost."
"It was a good feeling to finally embrace them, let them know I was safe after seeing all the casualties and people that were hurt," he said.
"But the mission still continued, and even though my family didn't want me to go back for safety reasons, for me, I still felt I had to go in every day."
He said one of the biggest things he learned that day is "we have so many great people out there helping each other."
"We tend to forget what we, as individuals, can do out there if we help each other out," he reflected. "So, of course, for me, this will never end, it's a dear part of my heart, it's in me."