The look of terror on people's panicked faces is what really struck Hanover Park runner Tom Jordan, who finished his first Boston Marathon about 90 minutes ahead of the blasts.
Jordan was resting about a block north of the finish line with runner Aimee Weber of Hoffman Estates, who works with Jordan at First Health Associates in Arlington Heights.
The health professionals were waiting to meet up with her family when they heard what sounded like cannons, which wasn't necessarily alarming to them considering the city they were in.
"We just kind of looked around asking, 'What was that?'" Jordan said. "And then we started to see the smoke billowing and just how scared everyone was, so we ran away.
"We knew it was bad, but didn't realize exactly what happened until we got back to the hotel and turned on the TV."
Cellphones weren't making any calls, but Jordan realized that text messages seemed to be getting through. That proved to be a godsend for a man who had just finished the race and couldn't find his family in the chaos.
"He had no way of contacting them, so he used the phone," said Jordan, who's run a dozen other marathons. "He was really grateful. The not knowing must have been really hard."