While they are trained to examine dead bodies for a living, the unstopping work and violent scenes they must hone in on for hours at a time can have harmful effects on their mental health, requiring counselling months after the incident.
Here, coroners speak of their experiences responding to tragedies that tore at the fibres of their communities.
A medical examiner's main priority after a mass shooting is getting all victims autopsied quickly so that they can answer any questions victims' family members have.
And their work is crucial in the aftermath, as what they find can be used in court to convict criminals responsible for mass devastation.
Dr Brian Peterson, who is president of the National Association of Medical Examiners (NAME), said that if a medical examiner were to take their time, it would prolong the grief process for victims' loved ones.
"The longer you take, the more you're holding them up," he said.
Dr Peterson practices in Milwaukee, Wisconsin, and his office responded to the 2012 shooting in Oak Creek, Wisconsin, in which a gunman killed six people in a Sikh temple.
Dr Stephany said that the process of explaining victims' violent deaths over and over to relatives was trying.
"The main question they want to know is: did my loved one suffer?" Dr Stephany said.
And answering this question honestly can be difficult, Dr Peterson explained, adding that he does not sugar coat what he presumes happened to a victim if he believes they were capable of experiencing pain when they died.
"I try to walk a careful line there. I'll give a technical explanation "of what happened to their body", Dr Peterson said. He added that if someone died an instant death - which he said is rare - he is happy to share that with their family members.
Dr Stephany said that in some cases, family members of the Orlando shooting victims did not want to speak with his team.
"Some people are in denial," he explained.
Even though medical examiners are used to the kind of work that they have to do following a mass tragedy, the sheer number of bodies they receive can be mentally overwhelming.
"You're thinking about the horrific nature of this stuff [but] we see it all the time. A lot of it is internal," Dr Peterson explained. "Each one of them is our patient. We're doctors too."
Dr James Gill, chief medical examiner at the office in Connecticut that autopsied the victims of the Sandy Hook Elementary School shooting, said: "We're used to seeing people shot, but when you see it on a massive level, that takes a toll."
Christian Burgess, who oversees a mental health resource available to people in the US who have been affected by or responded to a natural or man-made disaster, echoed this notion.
Burgess said that it is important to remember that, even though medical examiners are accustomed to studying dead bodies, they are still human. "We think they have a high degree of resilience," Burgess explained.
He added that, even so, coroners need to prioritise their mental health in the days following their response to a tragedy.
Dr Gill said that even staff members in his office who had worked there for years needed counselling a year after the Sandy Hook shooting, explaining that they experienced symptoms related to PTSD.
Without a doubt, the fact that they were autopsying so many children added to the crushing emotions, he said. "It's so unexpected to see elementary school students. There's so much innocence there."
Burgess said that if medical examiners experience seemingly mild symptoms such as having trouble sleeping, concentrating or performing day-to-day tasks after a mass shooting, they should seek help from a professional.
"Even mild symptoms can escalate over time. All of this can lead to depression," he explained, adding that feelings of hopelessness, despair and shame can plague coroners after witnessing trauma-inducing scenes.
No matter how "used to it" medical examiners appear to be, Burgess said, they can still be troubled by the exposure to tragedies. "Any of these people are at risk following the disaster."
Often, though, coroners do not fully understand what they are experiencing and helping with until after the disaster has come and gone.
Because their first response is to throw themselves into their work, they often do not let the weight of the tragedy sink in until after the fact, Dr Stephany said.
"We didn't really grasp the concept," of the deadliest US shooting, he explained.
"It took less than a year-and-a-half for them to take that title," he added, referring to the Las Vegas shooting.
On Monday, he sent an email to Clark County's medical examiner Dr John Fudenberg, who is now autopsying the Las Vegas shooting victims.
The email let Dr Fudenberg know that he is supported, Dr Stephany said.
In addition to the emotional trauma, the overworked coroners experience physical exhaustion after having to spend hours on end contemplating violent scenes.
"You all of a sudden realise you're tired," Dr Peterson said about responding to mass shootings and staying on your feet for 12 hours at a time.
Since the opioid epidemic took effect, medical examiners' offices have been desperately understaffed because of the rising number of overdose deaths in the US.
Nevertheless, they have to focus their usual workload in addition to a staggering number of new bodies in the aftermath of a mass shooting, which feels like a balancing act.
The first thing that a medical examiner's office does after an event that results in mass fatalities is set up a family services centre, Dr Peterson said.
They set up an offsite base because, usually, their offices are not big enough to accommodate the number of bodies that are turned over to them, he said.
He added that coroner's offices have contracts with other states or counties, which state that, in the event that they are responsible for high numbers of victims, their office can turn to them for refrigerated space to store some of the victims until they can be examined.
Dr Stephany said that his team was prepared to work with other entities when tragedy struck his community.
"Since 9/11, we're constantly drilling for worst case scenarios," he said, explaining that these drills require his team to work with hospitals, law enforcement and other agencies.
But, even though they had drilled, the Orlando shooting proved difficult, Dr Stephany said.
His county medical examiner's office had to work with the FBI and the Department of Homeland Security, and they had not been used to working with federal agencies, he said.
And Dr Peterson emphasised that working together is crucial, saying: "For something like Las Vegas, it's a matter of co-operating."
In addition to having to figure out all agencies' roles after mass casualties are passed over to them, medical examiners have to focus on getting their job done as quickly as possible.
After setting up an offsite base, examiners try to identify the victims, which can be tremendously challenging in a setting such as the concert venue in Las Vegas 58 victims were at when they were killed on Sunday.
Even if they have identification on them, it could be fake. And often coroners have to turn to dental records and DNA to match a body with a name.
Although they are trained for the worst, the long hours and gruelling scenes medical examiners face after such incidences are a challenge.
Even through the overwhelming emotions that came with the autopsies, though, Dr Stephany saw a silver lining when his team was faced with a tragedy.
What surprised him was "how much this community united, even though it was a gay club.
"We got support from around the country. The vigil was 50,000 strong the next day."
"It could have been divisive, but it was not," Dr Stephany said.
AMERICA'S GUN CONTROL PROBLEM
Because of loose gun control laws in the US, the chance of an American being murdered by a gun is 25 times higher than the chances of residents in other developed countries.
The rate of homicides that involve guns is 20 times higher than those in other developed countries.
As of 2013, 88 Americans were killed with guns each day.
Homicides that involve guns shave one year off the life expectancy rate for black American males. Guns are more likely to kill black American males aged 15 to 34 than any other cause.
When four or more people are shot and killed - excluding the shooter - the event constitutes a "mass shooting", and from 2009 to 2016 there were 156 mass shootings in the US, which resulted in 848 fatalities.
Thirty-four percent of those shootings involved a person who illegally owned a gun.
About one-quarter of mass shooting victims in the US is a child.
And 42 percent of shooters who initiate mass shootings exhibit "red flag" behaviour before doing damage.
Sandy Hook (2012): 27 victims, killed by white male Adam Lanza
Pulse (2016): 49 victims, killed by Asian male Omar Mateen
Las Vegas (2017): 58 victims, killed by white male Stephen Paddock
Columbine (1999): 13 victims, killed by white males Eric Harris and Dylan Klebold
