The panic spread like a contagion, from terminal to terminal. When people saw others screaming and running, they joined in the stampede.
Security expert Bill Stanton told Inside Edition: “It's the herd mentality. Someone sees someone all panicked and they get panicked and it has that domino effect.”
It began at JFK's Terminal 8 at 9:34 p.m. with shots reported outside the security checkpoint.
Judy Rothman-Rofe was about to catch a flight to Los Angeles. She told Inside Edition: “Suddenly we heard loud screams and people saying get down get down! At that moment it changed to a scary situation.”
The panic spread to Terminal 1 at 10:15 p.m.
Audio from police radio has also been released. One officer can be heard saying: "Be advised Terminal 1, people are running out and yelling, 'active shooter.'"
As people fled, loud noises like doors slamming sounded like gunshots, which only exacerbated the situation.
Another wave of panic struck Terminal 2 around 10:30 p.m. when someone screamed: "Shots!"
Scenes like the events at one of America’s busiest airports have followed the all-too-real attacks earlier this year on Brussels and Istanbul airports, fueling more fear.
But what if there really had been an attack? Would you know what to do?
Stanton said: “I'm constantly scanning. I'm looking at people. I'm looking for exits. For instance, I know there's an exit to my left. I know if I have to get out to street level, right down these steps and I’m there.”
He added: “If something were to happen right now, all rules go out the window. I'm going to look to jump over this counter, see what's back there, [maybe there is] a place to hide barricade myself in or a separate entrance that goes downstairs.”
Stanton gave the powerful advice: "Whatever you need to do to survive, do!"