It's a year since the Boston Marathon bombings, a good time to go over the lessons learned. And the biggest one came out within seconds of the explosions - when ordinary people became first responders.
"These people had no medical training whatsoever," said an EMS workers of the people helping the injured at the scene of the Boston bombings.
At a Harvard forum just 11 days after the bombing, EMS workers said there's a good reason that of the 264 injured, only 3 died.
"Some people were just holding jackets over people to keep them warm, and I can't tell you home much that helps."
"Some, it was just as simple as direct pressure, pushing on a bleeding vessel."
"There were a number of people arrived at my emergency department, had they not had those interventions they would have died."
"Anybody who arrived alive at a Boston hospital, is alive today."
And that's the kind of reaction that Leonard Marcus would like to see in every community. He runs Harvard's National Preparedness Leadership initiative.
"When the moment comes, you have to be able to engage that system."
We're seeing that, just recently, on that Southwest flight, when a crazed passenger suddenly tried to open the rear door at 35,000 feet.
"We basically tackled the guy who was back there," said one of the passengers.
There were air marshals aboard, but the passengers got there first.
That's what Marcus was talking about - the idea that any moment, any of us could get the 'tag.'"
Marcus said, "When something like this happens, 'you're it.'"
So get a good night's sleep. You never know.