Const. Michael Chernyk turned in the witness box to look at a large freeze frame of the crime scene.

"Are you in that video clip?" prosecutor Elizabeth Wheaton asked.

The moment seemed to catch the Edmonton police officer off guard. He grabbed a tissue and appeared to fight back tears.

"Yes, I am," he said quietly.

Chernyk testified Thursday at the trial of Abdulahi Sharif, the man accused of running into him with a car, then stabbing him with a knife. Hours later, Sharif allegedly drove a U-Haul truck into downtown and intentionally ran into four pedestrians.

Sharif, 32, faces five counts of attempted murder, one count of aggravated assault, four counts of dangerous driving causing bodily harm and one count of dangerous driving.

He has pleaded not guilty to all charges.

Thursday marked the first time Chernyk has spoken publicly about his ordeal.

He was working special duty on the night of Sept. 30, 2017, assigned to traffic control for an Edmonton Eskimo football game. Standing in front of his marked police cruiser, he saw a car coming towards him and heard an engine accelerating.

"I thought the vehicle was going to hit me," Chernyk said as he wiped away tears. "The next thing I remember, I was going through the air and tucking my chin to my chest, so that when I landed I wouldn't hit my head on the curb."

This court exhibit video shows the alleged attack on Const. Mike Chernyk. 1:11

The constable said he landed on his back.

"The next thing I knew, is that there was somebody on top of me," Chernyk testified." And I could feel the top of my head burning and my hairline felt very wet. It was at that moment I realized there was a black male on top of me, stabbing me with a knife."

Abdulahi Sharif in the prisoner's box in Edmonton Court of Queen's Bench. (CBC News)

'Officer down'

Chernyk described the struggle over a kitchen knife with a 12-inch blade.

"I grabbed at the knife the male was holding to stop him from stabbing me," Chernyk said. "As soon as I did that, I could feel the male feeling around my duty belt for my service pistol."

Chernyk said he used his other hand to push the pistol further into the holster. He eventually fought the attacker off him and gained control of the knife.

He dropped the knife to the ground by his feet and called for emergency backup on his police radio.

The jury heard his radio call.

"Officer down," was all Chernyk said.

He pulled his pistol from its holster and aimed at his attacker, who began to run.

"I began to follow him, but I didn't know how badly I was injured," Chernyk testified. "I didn't want to create a problem for my fellow police officers responding to the area and not being able to find me. So I stayed by my marked police vehicle, in case I collapsed."

Staff Sgt. Dana Donald was the first officer to arrive at the scene.

A bloodstained knife next to the safety vest that was worn by Const. Michael Chernyk. (Edmonton Police/Court Exhibit)

He described seeing Chernyk bleeding from his head, holding a large knife in his hand.

"He was definitely shaken up," Donald said. "He was questioning his reaction: whether he should have used lethal force at that time."

Scarred forever

Chernyk thinks he was stabbed in the head three times that night. He confirmed he was wearing his ballistic vest at the time.

Police photo taken of Const. Michael Chernyk in hospital after his attack. (Edmonton Police Service/Court exhibit)

Wheaton asked the officer if he still has scars from that night.

Chernyk said he has one on the top of his head, another on the left side of his face between his eye and his ear.

"What was going through your mind during that struggle?" Wheaton asked.

"Trying to survive for my kids," Chernyk said. "I'm a single parent with two children."

"Were you frightened?"

"Yes," Chernyk said.

Sharif does not have a lawyer for his trial. So far he has declined to cross-examine any witnesses.