Samuel Arellano and his grandfather fled. They hid and ducked behind a truck west of Union Station. People trampled the boy, stepping on his back, as they also ran from a hail of gunfire.

On his right side, near his ribs and beneath his red Patrick Mahomes jersey, Samuel, 10, of Kansas City, Kansas, felt a sudden pain — sharp, as if he had been stabbed, he said.

“He was screaming. He was complaining real bad,” said his father, Antonio Arellano, 46, who, living five minutes away, sped to pick up his son on Southwest Boulevard. They thought Samuel had been hurt in the melee.

“When I got home, I lifted up his shirt. That’s when I saw the bullet hole,” Arellano said. They phoned 911.

The bullet hit a rib, landing millimeters from his lung. At Children’s Mercy hospital, doctors removed a slug. Samuel was released that night. He went to bed.

Hours later, he woke screaming, racked by nightmares that now recur every time he tries to sleep.

“I’m having flashbacks of what happened,” Samuel, a fifth grader at Junction Elementary School, told The Star on Friday. “I was dreaming about my grandpa, my uncle, my cousin. We’re walking. We hear gunshots. I start running and the bullets hit me — reliving the moment when that happened.”

On the first night, his father said, Samuel woke, crying from nightmares where he sees the shooters’ faces.

“He’s a little traumatized,” Arellano said.

He said of his father-in-law, Samuel’s grandfather, Victor Salas Sr., “He’s destroyed, too,” mostly racked by guilt, Arellano said, because Samuel, in the midst of the confusion, had said he thought he was shot. But initially, when family lifted his jersey, they didn’t see the wound. There seemed to be little if any blood.

For Samuel, as for the hundreds of thousands of fans who attended, the parade and rally for the Kansas City Chiefs’ Super Bowl victory were supposed to be part of a memorable and joyous day. Arellano and his wife, Aby, 34, had chosen to stay home. Samuel went at about 9:30 a.m. with his grandfather, together with his uncle, Victor Salas Jr., and cousin, Isaac Salas, also 10.

“He’s a solid Chiefs fan. I mean he watches every single game,” Arellano said.

Then the bullets flew.

“I was extremely scared,” Samuel said. “I knew I got shot the first second.”

He wore his No. 15 Mahomes jersey over two other shirts. He later found a bullet hole through its right sleeve. Arellano said his family erupted in panic when they saw Samuel’s wound.

“It was more everybody that was around him that was in shock,” said his aunt Eunice Salas. “He (Samuel) was calm. He was being very, very brave.”

Samuel said that he knew he would OK, as soon as the ambulance came.

Twenty-three people were shot Wednesday, with 43-year-old Lisa Lopez-Galvan of Shawnee killed at the scene. Half of those struck were children age 16 or under, authorities have said. Two teens have been charged.

Arellano said he is not worried about his son’s physical recovery. The family is grateful Samuel is alive.

“We got lucky,” Arellano said.

They are also keenly aware that his psychological healing will take longer.

“That’s my only concern,” Arellano said. “We’re going to try to get him help on that.”

Samuel needs no help with one decision. It’s about the Chiefs.

“If they win another Super Bowl?” he said. “I’m just going to watch the parade on my TV.”