Dr. Mitchell Lunn rode in on the No. 1 bus from Cambridge and nervously walked into the massive Boston Marathon medical tent just before 7 a.m. He headed straight to the section of worn concrete where he treated bombing victims last year and paused, taking in the moment.
“I’m going to be okay,’’ he thought.
Lunn was diagnosed with acute stress disorder, a sort of mental shock, after the 2013 race and has shed many tears since, most recently last Tuesday on the anniversary of the attack. But like hundreds of doctors, nurses, and other medical volunteers, he willingly returned to work Monday’s race, partly, he said, to make new memories.
“There is no way I wasn’t coming back,’’ said Rocky Auletto, a nurse practitioner from Ocean City, N.J. She was part of a triage team of four people who all were at their station again outside the tent’s Boylston Street entrance. “I had to finish the story.’’
The story’s end was exceedingly normal for a marathon. The 1,900 medical volunteers were busy, even frenzied at moments, caring for sick runners suffering from dehydration, cramps, hypothermia, dizziness, nausea, and bloody feet. Medical personnel treated 3,920 racers and bystanders over the course of the day, including more than 1,800 at the main medical tent and an annex a block away. The Boston Athletic Association reported that 172 people were sent to hospitals.
Many of these caregivers have volunteered together for years and race day is a happy reunion. The greetings this year felt a bit more heartfelt.
John Andersen, a middle school science teacher from Marlborough, was behind the tent microphone, directing traffic and requesting supplies, as he has for 15 previous Marathons. His wife was a triage nurse outside with Auletto.
On this Marathon Monday, doctors and nurses stopped by Andersen’s table to thank him for staying calm last year as he directed caregivers to move out runners to make room for bloodied bystanders, some missing feet or legs. “I saw things I was never meant to see,’’ said Andersen, who has no memory of his announcements during the crisis.
Chris Troyanos, medical director for the Marathon, arrived at the blocklong white tent at 4:30 a.m. By 9, row after row of black cots lined the walls, with the green Dartmouth Street bike lane running down the middle of the tent and four flat-screen televisions broadcasting the start of the wheelchair race. Sixteen new blue-and-yellow quilts, donated from around the world, hung from the rafters.
“I’m looking forward to putting some closure on last year and this is the place to do it,’’ Troyanos said.
Directly behind Andersen’s microphone stand, Elizabeth Mitchell, an emergency room physician at Boston Medical Center, helped spread mylar blankets on cots.
When the bombs exploded last year, Mitchell grabbed blue gloves and ran to the finish line.
The first patient she tended to was John Odom, whose legs had been pierced by shrapnel. She took his pulse, and then picked up pieces of a broken wooden fence and splinted the legs of a severely injured woman.
“Initially, I couldn’t get it out of my mind, the smells, the sounds, the sights,’’ she said. “It was hard to sleep because I kept hearing explosions.’’
On Monday, she surveyed the scene unfolding in front of her: volunteers carrying crates of water, others pushing wheelchairs, runners on cots with their feet elevated on white cardboard boxes and covered with blankets. “It’s good to see it look like this,’’ she said at about 1 p.m., before rushing off to order Gatorade and a straw for her first patient of the day.
Outside the tent, the waiting line of racers in wheelchairs was growing longer. Pierre Rouzier, a University of Massachusetts Amherst physician who is on the triage team, said his nervousness had disappeared hours earlier but he noted that he did stuff a tourniquet in his pants pocket this year, just in case.
Leslie Morse, a physician at Spaulding Rehabilitation Hospital, was working next to Lunn and hanging bags of intravenous fluids last year when the bombs exploded. When Andersen announced that doctors were needed at the finish line, she raced out.
Inside the tent, Lunn, then a resident at Brigham and Women’s Hospital, Stephen Segatore, an intensive care nurse from Tufts Medical Center, and several other medical providers tried to save a young woman. They frantically performed CPR for several minutes, as her stretcher was wheeled down the green bike lane, before a supervisor told them to stop, that she was gone. They found out later she was Krystle Campbell, a 29-year-old restaurant manager and one of the three people killed in the blasts.
Segatore ended up seeing a trauma therapist and taking a medication to suppress nightmares. He, too, returned Monday.
Lunn and Morse, who briefly kept in touch by text after the bombing, asked to work together again. “The grief was so intense,’’ Morse said. “This is a fresh start for me here today.’’
As they treated runners, Morse asked a man stretched out on a cot how he was feeling. Lunn briefly glanced up from his patient, as three doctors lifted a woman in blue running gear who had fainted and laid her on a cot to take her temperature and blood pressure. An ambulance waited outside the billowing white flaps of the tent’s back entrance.
It was just after 2:49, the time of the first bomb last year. Lunn noted the time on his phone, and quickly walked over to Morse. They hugged briefly, then returned to their patients.
More from the 2014 Boston Marathon — Cullen: Just like the days we used to know | Gasper: Boston reclaims its Marathon | Photos: Marathon scenes | The ‘Scream Tunnel’ and Heartbreak Hill | The elite runners | Boylston Street | Videos from the Marathon | Full coverageLiz Kowalczyk can be reached at firstname.lastname@example.org.