VISTA, Calif. -- A police psychologist said a San Diego police officer's training and instinct left him with little other choice in a road rage incident in Oceanside, 10News reported.

Frank White is charged with recklessly shooting Rachel Silva and her son during a confrontation in an Oceanside parking lot last year.

Silva not only started the road rage episode but was the aggressor throughout, the psychologist said, and as it continued it left White with few options.

The incident occurred in a Lowe's parking lot, and White and his wife were being harassed and chased by Silva, police said.

"It was like a horror movie how angry and enraged this person was," White testified.

White said he felt he had a maniac on his hands.

"I thought at that point this person, if they have a chance, will try to kill me; they're out of their mind," he said.

As things escalated in the parking lot, Silva positioned her car next to White's driver's side door.

Testimony by psychologist William Lewinski revealed that action, coupled with everything that had happened prior to that, pushed White past a point of no return.

"If they are caught inside their vehicle it's their coffin. They need to get out of it so they won't be locked into a position of having to shoot," said Lewinski.

White fired several shots at Silva's car, but what he did not know was that her 8-year-old son, Johnny, was in the car.

"As a parent, I can't ever picture somebody putting a kid in that situation," said White.

Though Silva had twice the legal limit of alcohol in her system, as well as marijuana and methamphetamine, White is charged with negligent discharge of a firearm and displaying a firearm in a threatening manner.

Lewinski said, "I can't remember when an officer drew a weapon against an unarmed person and that person attacked the officer."

Silva, charged with driving under the influence and child endangerment, is not testifying in White's trial.

The trial should hear closing arguments Tuesday or Wednesday.