Margaret Lerhe thought she stumbled on a “mock drill” when she heard gunshots and saw a man running with a rifle as she walked by Parliament Hill Wednesday morning.

As a former nurse, after all, mock drills were not uncommon at the hospitals where she worked.

“It looked theatrical,” she said.

But when she heard a man yell “call 9-1-1” as he hovered over an injured soldier, Cpl. Nathan Cirillo, at the National War Memorial, she knew it was very real.

“I went over and asked what I could do,” she told The Sun last night.

She put pressure on the man’s wound while another woman performed CPR.

“His comrade and the other bystanders, we focused as a team,” said Lerhe, who lives in Ottawa.

“It was not heroic, just everyone stepping in to do their duty.”

Medics arrived on the scene moments later. One of the first was the chief of the Ottawa Paramedic Service.

Anthony Di Monte was at a morning meeting with top brass at City Hall talking about Ebola planning. The meeting finished, he grabbed a coffee and headed out of the building in his unmarked emergency vehicle.

“I had the radio on and I hear a cardiac arrest at the cenotaph. That’s how the initial call came in,” Di Monte said Thursday.

Realizing he was only 30 seconds away from the scene, Di Monte headed to the War Memorial to lend a hand to his paramedics also en route.

Di Monte arrived at the memorial and saw Cirillo on the ground with Canadian Forces members and bystanders already helping the injured soldier.

That’s when Di Monte saw blood and knew it wasn’t just a run-of-the-mill heart attack. It’s a gunshot wound, they said.

“They were doing good CPR. They really did an awesome job,” Di Monte said. He checked Cirillo’s pulse and asked more questions about how the soldier sustained a gunshot wound, first questioning if it was self-inflicted, and then learning it came from an assailant.

“Right away we told everybody, unsafe zone, an active shooter, let’s clear,” Di Monte said. “We accelerate our clinical treatments. Some treatments we’ll do in the back of the ambulance instead of on scene.”

In paramedic lingo, it’s a “scoop and run.”

An officer also boarded the ambulance since there was a victim of crime. Cirillo died in hospital.

But it wasn’t over for Di Monte.

A tactical paramedic delivered more shocking news as Di Monte was leaving the monument.

“He looks at me and says, ‘Chief, officer down, shot on Parliament Hill.’ We’re the closest so I look at him and say, okay, I’ll back you up,” Di Monte recalled.

They arrived at the Hill to help a security officer who was shot in the leg.

Then it was back to administrative work for Di Monte, but it included offering his advice to the emergency management team at City Hall and locking down paramedic headquarters.

“A little bit of a shakeup in my standard go to meetings and do budgets and haggle with people and talk to politicians,” Di Monte said.

Di Monte usually goes out with paramedics for a half day each month to help with calls so he can talk to his frontline staff and maintain his clinical skills.

“I’m a medic at the end of the day,” he said.

— With files from Shane Ross

Twitter: @JonathanWilling