Monday marks two weeks since the Boston Marathon bombings. Carlos Carballo, a teacher at Desert Hot Springs High School, took 14th place at the tragic marathon and says he's thankful to be back home and working on vertical and complementary freshman angles with his freshmen algebra class.
"When I came back the following Monday, students asked, 'How'd you do? We're so happy you're alive,'" said Carballo, of Cathedral City.
"Thoughts went through my mind of if he was OK," said ninth-grader Jose Ramirez.
Carballo finished the marathon in 2 hours, 17 minutes. He was the marathon's fourth-fastest American and ran his best race to date. However, the celebration of his accomplishment was quickly cut short.
"It just didn't seem right. I didn't want to celebrate either. People had just suffered. It wasn't just runners, it was family and friends, people who just came to support somebody," he said.
Carballo left Boston before the bombs went off, but questions of "what if?" remain top of mind for the runner and his fiancee Maria, who cheered him on from the same stands destroyed by the explosion.
"I'm just thinking what if I finished later in the day or stayed for an awards ceremony? It's kind of scary," said Carballo.
Unlike the Pythagorean Theorem, for him, the bomber's motive just doesn't add up.
"I just want to know why. More than anything, I hope you regret what you did and are remorseful because three innocent lives were taken away -- and four with the MIT officer," he said.
Running is a passion for the teacher, but he says the loss of life and limb will forever change his race.
"It takes away from my focus of a marathon. Now I'm just going to be wondering, Is the finish line going to be OK? Is that something I have to worry about?" he said.
Carballo says not next year, but he plans to one day return to Boston.
"I will eventually come back to Boston. It's great support. People are lined up from mile one to 26," said Carballo.