The calls came about an hour after the smoke cleared. At first, I found them undue.
"Stay safe." "Praying for you." "What a tragedy." There were motherly dispatches from around the world, fretting over the proximity of bombs and beloveds.
Of course we're safe, I wanted to say. Of course we're fine in Boston, this quiet bastion of Puritanism, cobblestones and colleges. We have emergency response systems. Our hospitals have electricity. Please hang on to your rations.
This is not Iraq, where over 30 died this week in bombings in three cities; not Afghanistan, where over 180 were killed in this month alone; not Syria, where 12 children died when regime jets bombarded civilian areas in Hassaka. This is Boston.
But something changes with indiscriminate killing. The stability of your inner world disappears. You discern a loss of comfort, of ease. You look carefully at bins. An adrenalin rush takes over as you navigate crowds, seeking exit routes and open spaces. Men with assault rifles start roaming your local Dunkin' Donuts. It is unsettling.
As a university student from Lebanon told me the day after the bombs exploded: "I'm used to this happening in my country. But this isn't supposed to happen here. This is supposed to be safe."
The psychological need for safety drove a lot of communication on Tuesday - not merely among separated runners and frantic families, but halfway around the world. There was a driving need to confirm that things were OK, to reassure and be reassured that Boston was still the same loveable curmudgeon despite this calamitous aberration.
In the streets, comfort came through small talk. Stoic police officers and haggard marathoners, bewildered visitors and braying locals commiserated in a way meant to produce a facsimile of normality:
"Nothing much going on hea," one US National Guardsman told me. "Just drinkin' my coffee and waitin' for the day to be ovah." Ah, Boston.
But the triteness disguised anxiety. "Please God, don't let it be one of us," is the refrain heard within Arab and Muslim circles. "Please don't let it be a student," is the mantra of those who remember "Unabomber" Ted Kaczynski and other home-grown terrors.
Others wonder to what degree the US security apparatus will turn its aggression outward. Will the effects of these explosions send drones, like angry hornets, ricocheting over regions of Pakistan or Afghanistan?
"What have we become?" Father William Hamilton, a chaplain with the Alcohol, Tobacco and Firearms unit asked me on Wednesday.
I don't know that "we" have. I know that it's difficult to secure a 42km marathon track. I know that within seconds, spectators were running towards the explosions, seeking to help. I know that #bostonhelp was spontaneously generated by Twitter users within minutes of the blast, and that free food was delivered to medical staff and police officers. I know that "peace" is scrawled in chalk across the doorstep of the home of Richard Martin, the 8-year-old who died while eating ice cream and watching the race. I know that students have sought to make sense of this. Boston University mourned 23-year-old Lu Lingzi in prayer on Tuesday night.
The usually boisterous Spangler Hall of Harvard Business School was sombre Wednesday as people wrote notes to the family of Krystle Campbell, a 29-year-old victim. At the Harvard Kennedy School, a large banner filled with well-wishes in Arabic, English, Hindi and other languages spans the cafeteria wall.
This is what we have come to, and will continue to embody. True, there will be reactionaries and paranoia and unease, too. Those things are the psychological shrapnel of this type of violence.
But that is not the majority, and it is not the way I choose to define this moment. The spontaneous good that is born of community is what has pervaded the past few days. It is the same good that caused phone lines to clog on Tuesday as people sought one another; the same good that launched a barrage of messages from Abu Dhabi, Tehran, Istanbul and Ramallah into my inbox.
At first I thought the messages were undue, disproportionate. Now I realise they were necessary.
Effie-Michelle Metallidis is a master in public policy student at the Harvard Kennedy School