LAKESIDE, Calif. – In a split-second that will haunt this quiet San Diego suburb forever, 10-year-old Kiera Larsen became the smallest guardian angel anyone here has ever known.

On a sunny Saturday afternoon in the tight-knit community of Eucalyptus Hills, two toddlers (ages 1 and 2) were playing in a driveway when a parked white Mercedes GLE began rolling backward down the steep slope. The driver, a family friend who had just stepped out to grab something from the house, had accidentally left the luxury SUV in neutral with the engine running.

Security footage obtained by Fox 5 San Diego shows the horrifying sequence: the vehicle lurching into motion, picking up speed, heading straight for the helpless children who had wandered into its path.

Then comes Kiera.

The fifth-grader, visiting with her mom for a playdate, saw the danger before anyone else. Without a scream, without hesitation, she sprinted from the porch, blonde ponytail flying, and shoved both toddlers clear with every ounce of her 65-pound frame.

Neighbors say the impact sounded like a bomb.

The SUV struck Kiera full-force, hurling her several feet before pinning her against a retaining wall. The toddlers tumbled safely into grass, crying but miraculously unscathed.

“She saved them,” sobbed next-door neighbor Tammy Rodriguez, who witnessed the entire tragedy. “That little girl gave everything she had for those babies. I’ve never seen courage like that.”

First responders airlifted Kiera to Rady Children’s Hospital in critical condition: massive internal injuries, shattered pelvis, traumatic brain injury. Doctors fought for 36 hours, but on Monday morning, surrounded by her devastated parents and the two toddlers she rescued, Kiera was taken off life support.

She was pronounced dead at 9:17 a.m.

The driver, identified only as a 58-year-old woman who has cooperated fully with investigators, was not impaired, according to the California Highway Patrol. The incident has been ruled a tragic accident, though charges remain under review.

But in Lakeside, there’s no debate about who the real hero is.

“Kiera didn’t think—she acted,” said her father, Chris Larsen, voice breaking during a candlelight vigil Tuesday night that drew over 1,000 people. “She always said she wanted to be a nurse when she grew up because she loved helping people. She just… she didn’t get to grow up.”

At Winter Gardens Elementary, where Kiera was a straight-A student and beloved “playground mom” to the kindergarteners, grief counselors were brought in Wednesday. Classmates released blue balloons—her favorite color—outside the school, many wearing handmade “#KieraStrong” shirts that sold out within hours, proceeds going to the toddlers’ families.

The two children she saved (a brother and sister from the neighborhood) are physically unharmed, but their mother, Alicia Gomez, collapsed in tears when speaking to reporters outside her home.

“She was their angel,” Gomez said, clutching her 2-year-old daughter, who still asks for “the big girl who pushed me.” “My babies are alive because of Kiera. There are no words big enough.”

GoFundMe pages for Kiera’s funeral expenses and a planned scholarship in her name skyrocketed past $400,000 in under 48 hours. Local businesses are painting murals of wings and halos on storefronts, and the San Diego County Board of Supervisors voted unanimously Wednesday to rename the community park where Kiera played “Kiera Larsen Hero Park.”

CHP Captain Mike Harris called it “the most selfless act I’ve seen in 28 years on the job.”

“She made the ultimate sacrifice,” Harris told the crowd at the vigil. “Ten years old, and she taught every adult here what real bravery looks like.”

As dusk fell Tuesday, hundreds gathered at the accident site. Someone placed a tiny pair of pink sneakers at the base of the retaining wall. Candles spelled out “HERO” in the street where tire marks still scar the asphalt.

Kiera’s mom, Jennifer, whispered to the cameras through tears: “She always said she wanted to make the world better. She did it in one second. My baby saved two lives and lost hers. I’m so proud… and so broken.”

In a town forever changed by one little girl’s final sprint, the toddlers will grow up knowing the name of the big kid who pushed them out of the way.

And somewhere, a 10-year-old hero is finally at rest—wings earned the hardest way possible.