Mundane choices separated the living from the dead. The line between those who walked away and those struck down was randomly etched, by countless banal considerations.
Run faster, or slower. Stand here, or there. Eat now, or later. Take the kids to see the big finish, or to the playground.
All over the city Tuesday, thousands were replaying the decisions they had made, retracing the steps that saved them by hours, minutes, seconds.
On Arlington Street, a crowd had gathered to stare at the closed-off, trash-strewn canyon that is now Boylston Street. Discarded foil blankets blew about like shiny tumbleweed. There was nothing to see really, but still people stood transfixed. A few bouquets had been placed at the barricades. A couple of TV reporters barked into microphones. A woman passed through the crowd, holding two red-haired girls by the hands.
“You don’t need to look,” she told them.
Dave Meyer and Debbie Schmitz stood there too, their faces grave. Meyer, from Chicago, ran his first Boston Marathon on Monday . It was “a once in a lifetime thing,” he said.
He finished an hour before the explosions. Schmitz, his girlfriend, had been waiting for him to pass by at a cafe right by the spot where one of the bombs would go off.
What if Meyer had finished later?
“I think about her, if she had been there,” Meyer said of Schmitz.
They went back to their hotel, and were just about to return to Boylston Street to meet Meyer’s assistant, who had also come to watch him run.
The spot the assistant chose to wait for them happened to be between the two explosions, far enough from each that she was unharmed, and able to send Schmitz a frantic text message: “Don’t come back bombs went off people r dead.”
Around the corner, Newbury Street was half-awake by lunchtime Tuesday, most of its windows dark. A group of young women walked down the street, handing white peonies to runners still wearing their blue-and-yellow Marathon jackets. Trash spilled from barrels onto the pavement, and people stepped over homemade signs: “GO Crane! 25 years.”
At the corner of Exeter, a few restaurant workers carried trays of foil-wrapped burgers past the barricades to investigators. Four friends sat on a low stone wall, checking their cellphones and sharing updates on the explosions. They had all been right here when it happened.
“I was right [at the explosion site] 40 minutes earlier,” said Joshua Picton, a 23-year-old retail manager from England who had taken his lunch break to get a glimpse of his first Marathon. “It was absolutely incredible. There was such a good vibe around. They were five or six deep there.”
He was back in the store when the explosion shook his building.
“If I had gone to lunch slightly later . . . ,” he said.
“It’s a blessing in disguise that we had to work,” Caitlin Maynard said. If she hadn’t been working, she would have insisted her friends Lauren Sacilotto and Alexandra Cipriano – fellow students at nearby Bay State College – join her right at the finish line.
Instead, Sacilotto and Cipriano, who had been watching the finish on the block where so many were injured, met her for a late lunch.
“If they had decided not to wait for me, they probably would have been there,” Maynard said.
Five minutes after they sat down to eat, they felt the blast, Cipriano said, “like something was falling on the building.”
She and the others are left to wonder about what might have been. “I’m too scared to walk down Boylston Street now,” Sacilotto said.
The thing is, walking down Boylston, or not walking down Boylston, makes no difference. There was no fail-safe way to avoid the random mayhem of Monday, no way to protect yourself from lurking senselessness any day, short of shutting yourself off entirely.
Terrorism is only effective if we let it freight everyday choices with debilitating significance. And so, the best way for those preserved by luck to honor the deaths and injuries of those whose choices led them to that one cruel spot is to keep living as if there is nothing to fear.
But in a grieving city, a city full of second thoughts, that seems like too much to ask right now.
Yvonne Abraham is a Globe columnist. She can be reached at abraham@