Marathon Monday starts early with registration for runners and a briefing for thousands of volunteers. Because of last year’s record heat and humidity, race planners and volunteers put in extra time to make sure everybody was ready for the possibility of excessive heat. The Boston Athletic Association (BAA) works to ensure every runner gets world-class health care at all times.

That day, I worked in a new role as the Bus Triage Physician. School buses pick up runners unable to complete the race and deliver them to the end. There is an occasional sick runner, and the goal is to get the right resources to the right patient. As I arrived at Medical Tent A, I met my team – another physician, two nurses, a registration person, and a direct line of communication with the EMS.

As the day started, we had a chance to ready cots and organize resources. The goal was to be ready as the elite runners and wheelchair racers crossed the finish line. Runners began to cross, and the tent came to life. Teams of nurses, athletic trainers, doctors, and massage volunteers rushed to help each runner. People with orthopedic injuries and various ailments came to us. We started to hit our stride. The ICU section scooped up the sick patients as Boston EMS readily transported seriously ill people with ease, and communication with all aspects of the marathon course was up and running.

‘At the time of writing this, almost 2 weeks later, I’ve had trouble getting back to normal. Vivid memories, graphic dreams, and symptoms I’d never experienced before in my life.’

And then, everything changed.

Waiting for an inbound bus of runners, I was making small talk with some of the Boston PD who helped at the finish line. We heard a blast, and I remember saying, “Why is there a cannon?” The police were immediately on edge, then another blast. I vividly recall the lapel microphone of the police officer in front of me raining with static and screams. I immediately ran back into the tent. As I entered, there was just enough time to see one of my colleagues rushing to his backpack. He stood up and started putting on tactical body armor.

The pace in the tent rapidly picked up, and I recalled thinking, “Uh oh.” We moved tables and arranged equipment as best we could for the unknown coming shortly. We didn’t know what happened, but we knew it was bad.