Christopher Deedy couldn’t quite figure out what was happening.

He’d told the guy he was a cop. He’d even showed him his badge.

And yet the guy in the McDonald’s seemed to get even madder.

“That was not what I’d expected,” the 29-year-old U.S. State Department special agent told a Honolulu jury on Tuesday. “That was not what I’d anticipated or what I’d hoped for.”

Deedy is on trial for the Nov. 5, 2011 killing of 23-year-old Kailua resident Kollin Elderts in a Waikiki McDonald’s. He’s been charged with second-degree murder in a case the prosecution says occurred because he was drunk, inexperienced and was carrying a gun even though he was off duty and out drinking with friends.

Deedy took the stand in his own defense Tuesday, walking the jury through his encounter with Elderts, sometimes breaking the narration down second-by-second as he followed along with a McDonald’s surveillance video that had been recorded that night.

His purpose seemed clear: convince the jury that he followed his law enforcement training in trying to defuse what he thought was an escalating, violent situation.

Up to this point the 18-day trial had centered on the testimony of police and other witnesses who were at the Kuhio Avenue McDonald’s the night of the shooting.

Much of the testimony has been conflicting, including whether Deedy identified himself as a police officer and whether he was the instigator.

On Tuesday, Deedy described in calm, professional detail what steps he took to assess the situation — he believed Elderts and his friend Shane Medeiros were threatening another customer — and to handle what seemed to be aggressive behavior.

Deedy recounted how a commotion at the McDonald’s counter caught his attention. Elderts was “laughing sort of hysterically” and picking on another customer who asked to be left alone. The cashier also asked Elderts and Medeiros to stop, he said.

Loud behavior, the time of night — it was about 2:30 a.m. — and people possibly under the influence of alcohol. Those are all things “we’re trained to look for,” Deedy said.

When he heard Elderts ask the customer “want beef?” — do you want to fight — he walked up to Elderts’ table and asked him what was going on.

“From my trained perspective I believed that it was appropriate for me to intervene, to further assess the situation because this was not a mutual interaction going on,” Deedy said.

The men continued to argue, voices raised. Other customers joined in and a small group, including a restaurant security guard, gathered near Elderts’ table.

Deedy said Elderts challenged him directly. “He said something like ‘hey fucking haole you like beef too?’”

Deedy said he’d not heard the word haole until a few weeks before he traveled to Hawaii. A friend from the islands told him what it implied. “He said don’t worry about it but if somebody says fucking haole to you that’s not a good thing.”

Minutes passed and the confrontation did not seem to be calming down. Deedy said Medeiros seemed inclined to let things go but Elderts got even angrier and made physical threats.

“I needed to portray a stronger command presence,” Deedy said, so he identified himself as a law enforcement officer. Other witnesses in the trial have testified that Deedy never said he was a cop.

But defense attorney Brook Hart handed Deedy his leather wallet with his gold shield in it and had him demonstrate to the jury how he slipped it easily out of his right back pocket and flipped it open, the badge clearly displayed. Deedy pointed out on the McDonald’s surveillance video a view of him with his “creds” openly displayed.

The fact that he was a cop did not seem to sway Elderts, Deedy testified, and that threw him off. In training, he said, they are taught that simply identifying yourself usually calms a situation down.

But Elderts continued to act aggressively, taunting Deedy and telling him to just go ahead and shoot him, finally standing up and moving out from behind the table, Deedy said.

“I think I was in actual shock,” Deedy said. “This was very quick, there was a lot going through my head.”

“My brain was going a thousand directions,” he said.

Hart asked him why he didn’t just leave the restaurant. A convenient escape route was just steps away through a side door.

But Deedy said as a trained law enforcement officer he couldn’t responsibly walk away from a situation he’d already become part of.

“I interjected myself in the situation because I sensed the propensity for violence,” he said. “For me at this point to run would be irresponsible.”

Tuesday’s court session ended just after Deedy described how he’d tried to physically disable Elderts with a kick to his left leg. He missed his target — Elderts’ shin — and instead the blow landed on the meaty part of Elderts’ thigh.

Elderts grabbed Deedy’s foot and managed to pull of his slipper. And the way he did that made Deedy realize that Elderts was a more formidable opponent then he’d first thought.

He called it an “oh shit” moment.

Deedy is expected to resume his testimony on Wednesday and guide the jury through pulling the trigger. The prosecution also will have an opportunity to cross-examine him.

Deputy Prosecuting Attorney Janice Futa has continually attempted to paint the federal agent as the first aggressor in the fight between him and Elderts. The kick is one of the elements she has cited as evidence that Deedy started the fight.

Hawaii’s self defense law specifies that a person cannot provoke someone into a fight with the intent of using deadly force as a response.

But Deedy is portraying himself as having taken reasonable steps to defend himself and others.

Deedy’s defense team has characterized him as a law enforcement officer, which could play a factor in whether the jury believes he was justified in shooting Elderts.