BRADENTON -- Katie Powers was taking a runner's blood pressure when the first bomb exploded across the street from the Boston Marathon's large medical tent.
"I heard this tremendous sound through my stethoscope and I went, 'Whoa! What the heck was that?!'" said the Manatee Memorial Hospital perinatal educator. "First, we thought it was a cannon firing. We had no idea.
"Then the next one went off."
The iconic American sporting event's finish line had become a war zone.
Working her fourth Boston Marathon as a volunteer, Powers was right in the middle of it.
Back at home Wednesday, she talked about the tragedy that claimed three lives, injured more than 170 and staggered a nation.
"When people started coming in covered with soot, that's when we knew it was bad," said Powers, who'd been on station since 8 a.m. "We made the immediate switch from a very sophisticated first-aid station capable of handling anything to becoming a trauma unit."
What the registered nurse of 30-plus years saw was extreme.
A person with their legs blown off.
A person bleeding from their ears.
People with shrapnel wounds.
"I've never been in battle," said Powers, whose two sons served in Iraq and Afghanistan. "But there were what I assumed were shrapnel wounds in legs, feet and arms. Some people had head injuries, because they were blown back and knocked down by the explosions."
The tent was cleared except for doctors and nurses, who were instructed to stay.
"Everyone was calm, worked as a team, focused on our patients," Powers said. "Many of the physicians were ER doctors, but we also had cardiologists and family practice doctors as well."The nurses ranged from veterans of emergency rooms and VA outpatient clinics to mother/baby nurses like Powers, who cut off clothes, cleaned wounds and comforted the injured.
"I prayed with co-workers and victims," she said. "I prayed the Our Father and the prayer of St. Michael: 'Protect us from the wickedness and snares of the devil.'"
At Monday morning's medical meeting, volunteers had been told emphatically to focus on one runner at a time.
"I remember thinking later -- one runner at a time, one victim at a time," Powers said. "I gave my best at a moment when I felt I was needed. I was blessed to be able to care for those innocent people.
"Out of this horrible thing that happened, the fact we were so close by probably saved a lot of lives."
Andrew Powers can appreciate his mother's experience amidst the catastrophic change of events.
"It's a huge leap," said the Manatee County EMS paramedic/firefighter. "We train for traumatic events, but they were not expecting anything like that and responded well. I'm proud of her."
Powers tried to contact all her five children, who knew she was helping in the Boston Marathon medical tent as in years past.
"I didn't know what she was calling about. I thought it was a misdial," said son, Brendan, a former Marine. "Then I got a text from my sister: 'Mom's OK. It's like a war zone.' I'm like, what? Then I looked online and saw what had happened. But I knew Mom was OK."
Katie Powers and the rest of the medical team evacuated the tent almost two hours later when authorities suspected another bomb nearby.
Before she left the area, she made a promise.
"I'll be back next year," Powers said. "These bastards can't keep me away."
Vin Mannix, local columnist, can be reached at 941-745-7055. Twitter: @vinmannix