When Eve Thomas found paramedics treating her badly injured father at the scene of a crash, she was surrounded by people taking photos and videos to share on social media.
Loved ones were then mistakenly told that Eves father had died, because online speculation travelled faster than the truth.
Eve has backed a campaign urging people to think before sharing images of traumatic events, supported by emergency workers who say these actions interfere with their ability to save lives and preserve dignity.
Insp Nia Lambley said there had been a "seismic change" in the behaviour of onlookers at the scene of emergency incidents, with phones often used to capture images rather than to call for help.
Eve, now 25, was 17 when her father, Nigel, was knocked off his bicycle returning home from work as a delivery driver in Hirwaun, Rhondda Cynon Taf.
Her school bus was among the traffic that stopped at the scene in the immediate aftermath, and she saw that her father was involved.
"I was essentially on a bus full of other children that were filming and taking pictures and it was incredibly distressing," said Eve.
"He was treated by the air ambulance and people filmed his treatment."
Nigel had sustained a severe traumatic brain injury and numerous other physical injuries. He was in a coma for a month and spent about nine months in hospital.
Eve said having the incident documented and discussed online "took on a life of its own".
"He was at a very vulnerable point and didnt have a voice in that - he couldnt speak on any of it, and people were sort of doing that for him - putting that narrative out there, that wasnt necessarily true."
While friends attempted to have material taken down from various online platforms, the fact that it was filmed or photographed at all is something that Eve has struggled with.
"Even if its somebodys old phone is in a drawer, theyve got my fathers worst moment in his entire life on there," she said.
"Even if weve managed to get [the images] taken down, the impact of knowing that people would do that stays.
"If it was you or someone you loved in that situation, would you rather have someone take a minute and think - or call for help - or would you rather them film it and preserve that?"
Insp Lambley from South Wales Police is urging people to use their phones to call for help, rather than to livestream a persons final moments.
"Were trying to give people as much dignity in that vulnerable moment as possible," said Insp Lambley.
"When people whip their phones out and take photos of them or video them, were losing control of that. Were not able to give them dignity."
She said there had been a "seismic change" during her 13 years as a police officer.
"Now it just seems the go-to is that instead of people using their phone to call for help, theyre using it to film and upload to social media for nothing more than likes and comments.
"Its not with the intention of bringing anyone to justice or to assist that person in any way - youre robbing that person of dignity."
The campaign, Its Not Your Story To Tell, has been co-produced by Ms Thomas and the South Wales Trauma Network, which is made up of hospitals, emergency services and rehabilitation services.
Insp Lambley said police being filmed by members of the public is common, and said she accepted that officers must be held accountable.
"But when we see the impact it has on people that were dealing with as victims of crime or traumatic incidents like car accidents or stabbings, it really hurts, because it completely contradicts what were trying to do.
"On some occasions theyre using their phone to livestream people in - sometimes - their last moments."
She recalled one incident where a 15-year-old boy had died and after attempting to resuscitate him, she and colleagues became aware that a member of the public had taken a photo and circulated on social media that the teenager had died.
She said she had been trained to deliver "a death message" with dignity, meaning they would take time to compose themselves before breaking the news to relatives.
"In this case I literally had to run from the scene to the house of this boys parents, looking dishevelled and out of breath and bang on their door and say Im really sorry, your son is dead.
"Thats not how I ever wanted to deliver that message, but I felt I had to get there before social media. Youre running against something that you have no control over.
"For me, I did a disservice to that family.
"But I intercepted somebody who was on their way to give their condolences, and more or less push them back from the front door, saying the [family] dont know."
The campaign was initiated by the South Wales Trauma Network because of the impact the issue has on a number of affiliated professions.
Andrea Bradley, operations manager for the network, said having someone record your efforts to support a person in their hour of need had "a negative experience for everyone involved", including the professionals.
"I think its really important to highlight the effect on staff too," she said.
"When people are recording them actually trying to save a life the effect is huge. Its a huge responsibility on that member of staff.
"I have never forgotten any patient that has been involved in any sort of serious accident - or their family and loved ones. They stay with me forever.
"We reached out to every blue light service and asked them about the impact - every one of them came back and said we have an experience that is negative and we want to be part of this campaign."