Zaccardi testified that he knew the others were likely agents from the Weber Morgan Narcotics Strike Force executing the same search warrant, but he blocked it from his mind.
Until he saw Agent Kasey Burrell wheeled past him in a wheelchair, his head covered in blood.
Then, Officer Michael Rounkles came around the corner in a stretcher, offering Zaccardi a thumbs up as he went past.
Sgt. Nathan Hutchinson then walked past Zaccardi, telling him he had also been shot. Also wounded that night was Roy Officer Jason VanderWarf.
Killed in the shootout was 30-year-old Agent Jared Francom.
"For the first time in my career, I had this moment of panic, where I didn't know what to do," Zaccardi said.
Zaccardi was one of four people who testified Wednesday during the preliminary hearing for shootout suspect Matthew David Stewart. The hearing is scheduled to last through Friday and will determine if Stewart will stand trial.
Stewart, 38, is charged with aggravated murder and eight other felony counts relating to the shooting and marijuana cultivation. Prosecutors have said they will seek the death penalty.
In an opening statement, Deputy Weber County Attorney Gary Heward told Judge Noel Hyde that all of the bullets recovered from Francom's body were 9mm, the type of weapon Stewart was shooting that night. Police were carrying .40-caliber pistols, Heward said.
Investigators became aware in September 2011 through their telephone tip line that Stewart had allegedly maintained a marijuana cultivation for about seven years. On three occasions, officers went to the home for a "knock-and-talk" a tactic used to speak with homeowners but were never able to contact anyone, Heward said.
But while looking into the windows of the home, the officers spotted equipment they believed could be used for growing pot and they obtained a search warrant, he said.
Three law enforcement personnel who executed the warrant that night all testified Wednesday that they yelled, "Police! Search warrant!" before entering Stewart's home and while inside the house. They all said they were wearing some form of police identifier, whether it was a jacket with the word "police" written in bold, a bullet-proof vest with "police" printed on it, or a fleece vest with police insignia embroidered on the chest.
It was unclear Wednesday whether all of the agents who entered the home were wearing bullet-proof vests, though when Grogan testified about his clothing that night, he made no mention of a protective vest. All three said they were wearing jeans.
Grogan testified that when he stood in the hallway of the home, he saw an arm and a gun coming around the bedroom door. The shooter said nothing before he began firing, one of the first shots striking Grogan in the left cheek. Grogan said the shot resulted in the loss of teeth, a severed tongue and pieces of jaw being blown out.
Grogan was able to return fire, he testified, but his gun was soon empty and he was still inside the home. Eventually, he was able to retreat to a bathroom for a few moments, then escape to the side door through which the agents had entered moments before.
Francom also began firing to pin Stewart inside the bedroom, until Francom ran out of ammunition.
Stewart then shot Francom repeatedly, as well as other officers moving toward the bedroom, until there was a pile of officers just outside the room, Heward said.
Agent Derek Draper testified Wednesday that he was nearly shot in the hallway he felt the bullets brush past his hair but was able to retreat back outside. There, he found Rounkles, a uniformed Ogden police officer carrying a shotgun, and they went back towards the home.
Rounkles went inside while Draper waited outside. After a few moments passed, Draper testified that he found Rounkles in the south doorway, lying in a stairwell, with blood coming from his mouth. Draper helped him outside, and when he returned to the doorway, he heard a "gun battle" inside, and found Burrell lying in the stairwell, also covered in blood.
"I thought he was dead," Draper testified.
Draper dragged Burrell out of the home, and when he returned to the same doorway, another officer lay in the stairwell: Francom.
Draper pulled Francom from the home, and other officers assisted him in pulling Burrell and Francom into the street. Rounkles was taken by a patrol vehicle to the hospital.
While in the street, Draper testified that he looked towards the house and saw a silhouette standing in the front doorway beginning to take aim, then firing towards the injured men in the street.
Draper said he felt the bullets ricochet around him, but he was never struck.
"I thought I was going to get shot right there," he said. "I'm just waiting, and then the shots stopped."
Utah Deputy Chief Medical Examiner Edward Leis testified that Francom was shot six times: in the left chest, right abdomen, right upper back into his spine, in the right shoulder, left arm and left thigh. The shot to Francom's spine was likely the most lethal wound, Leis testified, as the injury would have paralyzed the officer.
Two other wounds the shot to his left thigh which damaged his femur, and the shot in the abdomen which damaged his internal organs were also likely fatal, Leis said.
Some of the bullets passed through Francom's body and were not recovered, and Leis said he could not speculate based on the wounds what caliber they were. He also could not determine the order in which the bullets struck the agent, but said that based on hemorrhaging in the body, Francom was alive when he sustained all six wounds.
Wednesday's hearing marks the first time that details of the raid have been aired in a courtroom. For Erna Stewart, Matthew Stewart's sister-in-law, the evidence was at times frustrating because it was all against her brother-in-law, and his side of the story has not been told.
"It is very frustrating," she said. "But patience is a virtue. We've been waiting 10 months, we can wait a few more days."
Francom's family declined to comment Wednesday.
The five injured officers are among about a dozen people who have been subpoenaed to testify this week.
At a preliminary hearing, prosecutors must show there is enough evidence for a case to proceed. The burden of proof is substantially lighter than it would be at trial, and Hyde is required to view the evidence in a light most favorable to the state.
During a February interview at the Weber County jail, Stewart told The Salt Lake Tribune that he thought a group of men had broken into his home to rob and to murder him. He said he believed two bullets struck him during the shootout, and that one bullet seemed to have struck his right hip and then entered his abdomen.
Stewart's defense team on Wednesday questioned whether a person would be able to understand the hollering of "Police! Search Warrant!" if the officers were not yelling in unison. They also had questions about whether agents in the strike force who often grow beards or wear a longer hairstyle than a traditional officer because of undercover assignments would be easily identifiable as law enforcement in the dark.
Stewart's family, and a handful of supporters from the community, have argued police were too aggressive in investigating him, and that Stewart is a victim of the drug war.
The Associated Press contributed to this report.