"I couldn't find my wife for 20-25 minutes, it was horrible," Corona said.
During those anxious moments, Corona said he imagined the worst -- until he finally found her.
"It was the happiest day of my life. I totally lost it," he said.
The Aliso Viejo residents were one of many local attendees and runners who participated in Monday's race.
"I heard dynamite explosions before and it was as loud as a dynamite explosion," said Lauren Case of Woodland Hills. "I couldn't believe it could be anything but ... it was right at the finish line. There was no other explanation for what that sound was in my mind. I knew immediately, and I said to my dad, 'Dad, a bomb just went off.'"
Former USC student Natalie Logan was about to finish her first Boston Marathon when her life changed forever.
"The last major thing that happened in our generation was 9/11, and I wasn't there for that. I was in California. It sort of had that same feeling of helplessness, seeing people being upset and knowing that something has happened but not being able to do anything about it," Logan said.
A group of runners from Cerritos were at the finish line when the explosions occurred. None of them were injured. And 10 members of the L.A. Running Club also participated in the Boston event, but they were also not injured. According to the club's vice president, Alan Culver, all the runners finished in 3.5 hours or sooner. The two blasts happened right after the four-hour mark.
Los Angeles resident Jennifer Hartman stopped at the 26.1-mile mark to take a photo with her running club. Then, she felt the boom.
"The immediate moment to me was just, 9/11. It was the cloud of smoke coming out, some people were running, some people were crying," Hartman said.
It was a very terrifying moment for people who had no idea what was going on. Video captured as the explosions were occurring showed participants running from the scene in complete fear.
"It kind of just puts your whole life into perspective when you're there for such a meaningful day and everything just kind of turns around," said Tara Salcido of Redondo Beach. "I had so much support from my family and friends today. It makes you just realize 'I need to be home here with my family'. It's an emotional day for everybody."