Editor’s Note: Mel Robbins is a CNN commentator, legal analyst, best-selling author and keynote speaker. In 2014, she was named outstanding news talk-radio host by the Gracie Awards. The opinions expressed in this commentary are solely those of the author.

Story highlights

3 friends from U.S. among those credited with averting terrorist attack

Mel Robbins: They went from vacationers to guardians

CNN  — 

They were on a packed train heading for Paris when gunshots rang out. Moments later, a shirtless Ayoub El Khazzani entered the train car with multiple weapons. Mark Moogalian, a 51-year-old American and author and teacher, moved on instinct “to protect his wife” and lunged.

Meanwhile, Alek Skarlatos, a member of the U.S. National Guard, had seen the gunman, too. All it took were three words, “Let’s go, go” and he and his childhood buddies Spencer Stone, a U.S. Air Force airman; and Anthony Sadler, a senior at Sacramento State, switched from vacationers to guardians, charging down the aisle of the train to help. Their heroism inspired Chris Norman, a British businessman, to join them.

Mel Robbins

They tackled the potential gunman on behalf of the over 500 people on the train. Skarlatos was slashed with a box cutter, Moogalian was already down, shot in the neck. There seems little debate that these men stopped an attack that easily could have been “true carnage”: the suspect is said to have had an AK-47, pistol, a blade and a bag of ammunition.

President Barack Obama commended their courage and President Francois Hollande awarded them France’s highest honor: the Legion d’Honneur.

We’ve seen it over and over again – ordinary people who become extraordinary heroes in an instant. Acting on instinct they run toward danger, instead of running away. They subdue a threat on a plane, a train or on the street.

You might think that heroism and courage are complicated matters, but they really aren’t. It doesn’t come down to training or experience, it just comes down to your heart signaling you to go and help. To pull a fire alarm, as a shooter fires shots in a crowded theater. To shelter others with your own body as a gunman walks down the school hallway.

The difference between those of us who freeze and don’t speak up, don’t help and those that do is so simple and so clear that even a 10-year-old can explain it. I know, because I talked to mine about the heroes on the train.

What he had to say was so simple and so awesome, I wanted to share it with you.

I asked, what is a hero?

“That’s a good question. A lot of people think that heroes are people that have superpowers, but that’s wrong,” he responded. “Not all people with superpowers are good. There are lots of bad guys with super powers, like the Joker, Loki, Dr. Octavius, and Magneto. So having a superpower doesn’t make you a hero. It’s how you use your power that makes you a hero.”

How do heroes use their power?

“They do it in two ways. They either protect you, or they make you feel better.”

Do you know any heroes?

“Yes, I know lots of heroes. There’s all those heroes that protect us: the police, firemen, the army, military guys that you’re always thanking, ambulance drivers, like the one who drove me to the hospital, she was a hero … But then there are the helper heroes too – like teachers, seeing eye dogs and doctors.”

What is one thing that heroes do that make them heroes?

“They always act. When something blows up and everyone is running away, the hero always runs to the blast to protect you. Or if it’s a helping hero like a teacher, they always walk up and ask you if you need help. It’s like they know inside them that someone needs their help. Heroes don’t need to be asked, they just know.

Have you ever been a hero?

“I don’t know … (stares out the window for a bit) … I’ve been telling my friend whose parents are divorcing that it will be OK. I text her every day to see if she is OK. She’s got no one to talk to and she’s really worried, so I want her to know she has me. I guess that kinda makes me a helping hero.”

Anything else you want to add about heroes?

“Yes, anyone can be a hero. You just can’t think about it, you just have do what is in your heart to help.”

Speaking to the press after the attack Chris Norman admitted that his “first reaction was to sit down and hide,” and then his heart signaled him to act. “OK, I’m probably going to die anyway, so let’s go.”

Hopefully none of us with find ourselves in a situation as terrifying as the one on the train. As President Hollande said at the French award ceremony: “Here are four men who with the help of others acted not just to save their own lives, but who also came to help others and saved the lives of others.”

In doing so, they reminded us that heroic deeds can come at any time, and in many forms. We all have the potential inside us, but we all have to be willing to do one thing: to act when our heart tells us it’s time to go.

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