The building began to cave in. It hit another structure like a domino piece and then, with a deafening sound, it broke in half.
Only a few minutes had passed, but it seemed much longer as the 8.8-magnitude earthquake battered Chile on Feb. 27, 2010. Concrete chunks, metal bars and shattered glass cut Rozas' back. His daughter, Fernanda, suffered only a scratch.
"I left the building with the feeling that I no longer owned anything in life, but I was grateful because my daughter and I were alive," said Rozas, a computer engineer who is now 44. "From there on, I started seeing life a different way, without attaching myself to material goods."
His physical wounds quickly healed, and he's mostly shaken off the psychological trauma while getting his life back together. Recently divorced before the quake, he has a new wife and is expecting a child early in March, and he has bought a new home.
Others have also recovered from the quake and accompanying tsunami that killed 521 people and destroyed more than 220,000 homes.
President Sebastian Pinera began his term a few days after the quake, and he's touring the hard-hit zone around Concepcion to showcase the progress of reconstruction under his leadership.
On Wednesday, in the coastal city of Constitucion, he inaugurated a housing complex where eight people died in the quake. Bells tolled at 3:34 a.
Pinera's government is trying to use the disaster to undercut the high popularity of Michelle Bachelet, who was president at the time of the quake and is widely expected to run in the election.
Pinera's administration says her government failed to alert the coastal population about the tsunami that caused havoc up and down the coast, wiping out cities like Concepcion, which is 300 miles (500 kilometers) from Chile's capital, Santiago.
But Pinera's foes are also making the quake's aftermath an issue.
While Pinera says reconstruction from the $30 billion in damages is 90 percent complete, his critics say that the real figure is closer to 60 percent and that life has not improved for many victims.
"Reconstruction is much more than building a house; it's the restitution of productive basis for work," said Nicolas Valenzuela of Reconstruye, a humanitarian group. "What good is having a place to live if you don't have a job?"
With thousands more homes still needed, hundreds of families will have to endure a fourth Chilean winter in wooden shacks, Valenzuela said.
The emotional impact is harder to quantify, though no less real.
Eight of the 79 residents in Rozas' old apartment building died when it crumpled. He suffered a long period of trauma. He couldn't sleep, he lost weight, and even today he tries to stay away from tall buildings.
Friends and family pitched in with food and shelter. His doctor prescribed sleeping pills to ease his panicky feelings at night.
Gradually, Rozas recovered. He no longer needs medicine to sleep, and is more at peace—although he stresses he's still anxious about the possibility of another quake.
Speaking about his new two-story home, he said: "I live on the first floor. The second, I just visit it."
Rozas says he shrugged off the loss of his possessions, including the mostly brand new furniture that he had put in the apartment he lived in for just two months before the quake.
Yet, it was a material object that aided his recovery—a 1993 Honda Integra LS that he bought only weeks before the earth heaved.
It was in the parking garage under the rubble of his apartment building. But Rozas' gut told him the vehicle survived somehow, and then a police officer called to tell him the car was in good shape.
"I knew it would be difficult to recover it because it was in an underground parking lot," Rozas said.
He persuaded authorities to let him inside the garage, where he photographed the car. "I broke down. My Honda was right where I left it."
A friend who is a civil engineer helped with plans to dig the car out, which officials approved. A company donated machinery and workers, and Rozas took a week off from work for the recovery effort.
He said the struggle was repaid when he was able to drive his prized car into the street.
"It was impeccable and I keep it that way," he said. "It's my pampered one. My daughter and I call it 'my jewel.'"