The police officer had just shot and killed an unarmed minority suspect who had been trying to flee.

A fellow officer's dashboard camera caught the aftermath.

Officer Grant Morrison walks away from the scene of the shooting, his head in his hand, reaches the side of his colleague's cruiser, and collapses, sobbing uncontrollably.

For minutes on end, all that can be heard on the video is a fellow officer repeating, over and over, "I've got you."

Barely able to speak, Officer Morrison stammers, "I thought he was going to pull a gun on me."

A colleague leans over, consolingly, and whispers. "Maybe he was, maybe he was.... You survived."

The actions of a Billings, Mont., police officer bear little relation with whatever transpired before and after Freddie Gray was loaded, handcuffed and unbuckled, into a police van in Baltimore weeks ago. Mr. Gray died a week later of a severe neck injury suffered while in police custody.

But the Montana dashcam video offers at least a glimpse into why many police look at the indictment of six police officers Friday in the death of Gray with no small amount of trepidation.

For years, prosecutors and the United States Supreme Court have given police officers wide leeway in their use of deadly force. Now, the terms of that societal contract are up for robust debate, at the very least. If they are to change – as protesters from Ferguson, Mo., to North Charleston, S.C., have demanded – the question is how much?

Many police officers agree they must be held accountable to the law. But they wonder if society recognizes the difficulty of the task they are often set, and whether in the anger of the present the pendulum of police reform could swing too far the other way.

"The big picture is that the police are always held accountable for what elected officials can’t provide for the people – for failed infrastructure and failed policy," retired Baltimore police officer Leon Taylor told Slate.

In Baltimore, the police were tasked with holding the line between impoverished West Baltimore and the gentrifying urban core. Whether the tactics Baltimore police have used are necessary to maintain law and order will be addressed – either directly or implicitly – in the trial of the six police officers.

If the officers ran afoul of the law, many fellow officers nationwide will want to see them held responsible.

"First of all, the fundamental purpose of law enforcement is to bring violators of the law to justice, even if those violators of the law are law enforcement themselves," Dana Schrad, executive director for the Virginia Chiefs of Police Association, told WBT-TV in Richmond, Va. "The officers will have their day in court and justice will be based on the evidence."

But there is a sense among some police that society does not appreciate the complexities and mental toll of a job where the ability to deal out death is holstered on your hip, and the authority to do it is a badge pinned to your chest.

"The public thinks the police are above the law, but the police see themselves as expendable," former Officer Taylor told Slate.

In the Montana case, Morrison killed Richard Ramirez at a traffic stop in April 2014. After being told several times to put his hands up, Mr. Ramirez, who was high on methamphetamines, reached into his waistband, Morrison told a jury at a coroner's inquest.

"I knew in that moment, which later was determined to be untrue, but I knew in that moment that he was reaching for a gun," Morrison said, according to Yahoo News. "I couldn't take that risk.... I wanted to see my son grow up."

A 2011 reaction-time study found that if an officer waits until an armed suspect raises his gun to shoot, the suspect will likely get off the first shot. The Montana jury found that Morrison was justified in shooting Ramirez.

The fallout from Ferguson, however, has begun to change the calculus of policing. An Ohio police officer won national praise for not shooting a murder suspect despite the fact that the man charged him with his hand in his pocket, telling the officer to shoot him.

Moreover, some police departments are working to open a dialogue with the black community.

"I'd much rather they shout at me at a town hall meeting at a church and get to know me afterward than not have a relationship," Dallas Police Chief David Brown told the Associated Press. After a police shooting has already happened, "it's too late to try to establish relationships."

The concern is that the passion of the moment could lead to a reverse prejudice.

"In my 20-year career as a law enforcement officer and 16 years as an attorney I have never seen such a rush to file criminal charges, which I believe are driven by forces separate and apart from the application of law and the facts of this case as we’ve heard them,” Michael Davey, a lawyer for one of the Baltimore officers, told the media.

Ultimately, however, those officers will have to explain themselves, some police say.

"Unfortunately I have to agree with the decision," Joseph Giacalone, a retired New York Police Department detective sergeant, told Slate. "Because I have no answer to why they threw him into the police van in the first place. What was the charge? Why did they arrest him? He didn’t commit any crime."

"A lot of the guys I’ve spoken to feel the same thing I do."