SAN RAMON -- The 94-year-old woman covered in soot was difficult for Peter Kravariotis to make out. Garen Kissoyan could see only her arm. Kirill Yantikov, disoriented by the dense smoke that extended from the ceiling down to his chest, dropped to floor to search for his two friends.

Before the 17-year-olds carried her out of the burning home, they all heard the woman's shrieks: "I'm on fire. I'm on fire."

A day after the daring rescue, the three California High School seniors returned to the boarded-up San Ramon home to tell how they sneaked out of class intending to get food at McDonald's and returned as heroes, a story that reached national newscasts and caught the attention of talk-show host Ellen DeGeneres.

"There was so much black smoke, and all you could see was flames," Garen said. "We couldn't even see the lady. She was covered in ash."

The 94-year-old woman was taken to a burn unit at a San Francisco hospital, where she was in critical condition Tuesday. Her daughter was also home but not harmed.

Peter, a goalie for the school's varsity lacrosse team, said he ate only an apple for breakfast and was hungry. Having finished an assignment early during a morning class, they sneaked off campus about 9:55 a.m., piled into Peter's car and were on their way to grab a bite at McDonald's when they saw a plume of smoke ahead. Why not check it out?

"We had to do something," Kirill would say later.

By that time, according to neighbors, smoke and flames were shooting from windows and vents, and loud booms -- thought to be oxygen tanks exploding -- shook the cul-de-sac of Scarboro Place. The next seven minutes were a blur for the boys.

Instinct took over as they rushed to a woman in the backyard talking on the phone to fire dispatchers. With a garden hose, they fought a losing battle against the growing flames until the woman said something about another person still inside.

California High School seniors, from left, Kirill Yantikov, 17, Garen Kissoyan, 17, and Peter Kravariotis, 17, pet the 18-year-old deaf and partly blind
California High School seniors, from left, Kirill Yantikov, 17, Garen Kissoyan, 17, and Peter Kravariotis, 17, pet the 18-year-old deaf and partly blind Jack Russell terrier they saved Monday from a burning home in San Ramon on March 18, 2014. They also saved the 94-year-old female resident. (Doug Duran/Staff)

Garen and Peter ran in through a door in the garage but could not get past the billowing smoke, so they ran to the front door. There, they met 76-year-old neighbor Bob Smith, who hollered that a woman was inside, but he didn't have the strength to pull her out.

With little visibility, they pushed through the haze, found the woman still seated on her chair and pulled her and her 18-year-old dog out. Garen said the woman's burned hair stuck to his jacket. Kirill, who had lost sight of his friends, eventually crawled out.

Firefighters arrived, venting the roof and extinguishing the two-alarm fire 45 minutes later.

The teens, who Peter said smelled strongly of smoke, returned to class, almost as if nothing had happened. They were soon called to Principal Mark Corti's office and shown a recording of them ditching school. But they also heard a voice mail from Smith, who pointed out their heroic actions and asked Corti to take it easy on them.

The teenagers said they have to serve four volunteer hours for the class they ditched, but they would do it again.

"It's better than them giving us a detention," Peter said. "If that ever happened again, I know we would go into a burning house."

Added their teacher, Kathleen Seabury: "In a situation like this, the true caliber of your character comes through. I'm not surprised -- they are good guys.

"They cut class, but at the end of the day things happened for a reason. It was meant to be."