CHICAGO (CBS) — Chicagoans and others from the Midwest who were in Boston for Monday’s marathon began arriving home on Tuesday, a day after two bombs at the finish line killed three people and wounded more than 170 others.

Marathon runner Matt Levine was still in disbelief as he returned to Chicago at O’Hare International Airport on Tuesday.

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“The thing is the explosions themselves were very, very tiny; and, to me, this is going to sound weird … but it’s like it’s not real. I can’t still believe that it happened,” he said.

Levine was about 200 feet from the first explosion, and about 100 feet from the second one.

The Crystal Lake resident had already finished the race when the bombs went off, prompting him at first to want to take off with his mother, who came to watch.

“When I realized that people were not going to panic and trample us – because that was really my first thought; it was for my own safety, and I think that’s just a natural thing – we went inside the mall that we had come out of when the explosions took place, and I said, ‘Hey, wait a second, maybe people need help,’” he said. “We turned back.”

Levine praised emergency personnel and volunteers for caring for the wounded.

Paul Patrick flew into Midway International Airport Tuesday morning. He finished the Boston Marathon long before the two explosions near the finish line. His initial thoughts were with those in the blast zones, then “as a runner, knowing that feeling when you’re facing the last 400 meters of a 26-mile race, and then see the finish line gone, and the spectators that lined the course were all evacuated, and you want to achieve that goal of finishing that race, and there was no goal to achieve.”

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Several runners said there was a great deal of confusion immediately after the explosions, as those who were a few blocks away at first thought cannons were being fired for Patriots’ Day, a local holiday in Boston.

“It was a very large boom, like a cannon. And the second one was even louder, and the smoke was even more billowy,” runner Diane Campione said as she returned to Chicago at O’Hare International Airport.

Berkley Cameron, who also flew into O’Hare on Tuesday, said “It was just kind of shocking. I finished the marathon, and I was getting my medal, and then I heard like a couple big booms, and I looked behind me, and I saw a big explosion; a lot of smoke and stuff. … At first people thought it was just like maybe a transformer had blown, or they were shooting off a cannon for Patriots Day, but I just had a bad feeling.”

Maggie Barney said many runners got together after the explosions to watch news coverage on TVs at local restaurants.

“All around the neighborhood that we were in, everybody was sort of gathering in small groups, and sort of kind of chatting, and a little bit of hugging of each other,” she said. “So it was just wanting to be safe, and be with others almost.”

Runners said the average time to finish a marathon is about four hours; approximately the same time the bombs went off in Boston on Monday.

Karen Sheehy, who also finished long before the blasts, said people knew where she was, and reached out through social media to find out if she was safe.

“Some of the cell phones were acting up, but text seemed to be, at least on my phone, coming through at a rapid-fire pace, to say the least,” she said. “From out of the woodwork; people you hadn’t heard from in a long time, that through social media knew where you were.”

Sheehy, 40, was celebrating her finish of the marathon with family when disbelief took over as they saw on TV the carnage that was unfolding a few blocks away.

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In Chicago, the Chicago Area Runners Association was planning a “unity run” at Foster Avenue Beach on Tuesday evening.