Naperville cardiologist Jim Ostrenga was six blocks away from finishing the Boston Marathon when he was halted by police cars in the middle of the race route.
"Thank God I was running a little slow today," Ostrenga said by phone from his hotel room in Boston. "Even though we were just six blocks away, with all the screaming and bell-ringing by the crowd along the route, I didn't hear the explosion."
Ostrenga was one of the first to be blocked from finishing the race, and eventually thousands of runners behind him were halted, as well.
"The police weren't saying anything at first and I thought it was a medical emergency," Ostrenga said. "After about 15 minutes I called my wife, who was back at the hotel, and asked her to turn on the news to see what was going on and that's when I found out about the explosion."
The crowd of runners that eventually gathered behind Ostrenga along the route reacted calmly about the explosion, he said.
"It wasn't chaos at all from where I was," Ostrenga said.
He was blocked from being able to assist medically at the scene and, after about 30 minutes of waiting, Ostrenga decided his race day was over.
"I was freezing," he said. "It was about 50 degrees with a breeze and none of us were wearing a lot of clothes, obviously. I hopped the fence and left."
Ostrenga found the bus carrying his backpack with warmer clothes and then hoofed it back the three miles to his hotel.
"I never thought anything like this would ever happen," he said. Normally, "it's a party atmosphere. Everyone is so happy. It's a very uplifting experience and there are police and EMS all along the route. You feel very safe."
Monday was Ostrenga's third consecutive Boston Marathon. He has yet to qualify for next year's race, but he said he'd have no qualms about returning.
"It is a great experience," he said. "And this is such a tragic, miserable thing that happened today and there was no reason for it."