He took a selfie.
"I had some time to figure out what I was going to do," said Chin, a National Geographic photographer whose images of extreme climbing by the Straits of Hormuz appear in the magazine's January issue.
"That's when I took the selfie," he told AFP. "It was one of those moments when, 'Well, I'm a Nat Geo photographer'. I had to document (the moment). It was pretty classic."
Self-portraiture has been around for centuries, but the global proliferation of smartphones with built-in digital cameras plus the ability to share photos instantly on social media has taken the genre to a new level.
With 2013 coming to a close, the publishers of the hallowed Oxford English Dictionary, arguably the final authority in anglophone lexicography, declared selfie to be their "word of the year."
(Also see: 'Selfie' is Oxford's word of the year)
"Selfie: noun, informal. A photograph that one has taken of oneself, typically one taken with a smartphone or webcam and uploaded to a social media website," according to Oxford. "Also: selfy. Plural: selfies."
Internet search provider Yahoo meanwhile estimates that in 2014, about 880 billion photographs will be taken. That's 123 photos for every man, woman and child on Earth. Many will be selfies.
In Britain, a survey for Samsung found that 17 percent of men, and 10 percent of women, take selfies because "they enjoy taking good-looking photos of themselves."
"I think 'selfie' is a term of endearment for the self, in a way," said Sarah Kennel, curator of photography at the National Gallery of Art in Washington, who admits to taking the odd selfie herself.
"It does reflect a kind of narcissism in our culture," she told AFP.
US President Barack Obama and British Prime Minister David Cameron got tongues wagging when they took a selfie with Danish leader Helle Thorning Schmidt at Nelson Mandela's memorial service in South Africa.
"What an incredible sign of the times," children's photographer Sarah Sloboda, author of the e-book "How to Take the Best Selfies," told AFP.
"That's the kind of thing you can put in a time capsule to represent this period."
No one knows if Obama and friends had even heard of Selfies at Funerals, an equally controversial Tumblr compilation of, well, selfies taken at funerals, mainly by young people.
"When a teen tweets out a funeral selfie, their friends don't castigate them," its founder Jason Feifer explained in Britain's Guardian newspaper.
"They understand that their friend, in their own way, is expressing an emotion they may not have words for. It's a visual language that older people even those like me, in their 30s simply don't speak."
The year also saw Pope Francis in a selfie with teenagers at the Vatican, as well as pop diva Beyonce turning up in a smiling fan's selfie in Australia, to cite a couple of Time magazine's "11 most memorable selfies of 2013."
From Los Angeles, gossip blogger Perez Hilton declared a pink-haired Miley Cyrus posing for herself in a skimpy Lil' Kim Halloween costume his favorite among countless celebrity selfies over the past 12 months.
But there's no need to be famous to become famous for a selfie.
Thanks to Reddit and other social media websites, goofy selfies of a proud twentysomething dad in the Pacific Northwest state of Oregon mimicking the faces of his newborn baby daughter went viral overnight.
"We just watched the camera screen and copied whatever face she was making," explained Eddie Wheeler to his fellow Reddit users.
In Norway, popular fitness blogger Caroline Berg Eriksen snapped herself in a mirror, wearing bra and panties, showing off a firm flat tummy just four days after she gave birth.
Critics branded her selfie a "disservice" to women, but Eriksen struck back, saying she took it and shared it "because I'm proud of myself and my body for something as tough as a pregnancy/birth."
And then there was the young woman in New York who snapped a selfie with the Brooklyn Bridge and an attempted suicide leap in the background. That image caused a stir when it made page one of the New York Post.
"A selfie is a sort of perversion (and) a conquest of social virtual terrain," said Paris-based travel photographer Jean-Francois Vibert, who blogs at www.macandphoto.com.
"Happily, perversion is not prohibited," added Vibert, who namechecks the flamboyant pop star Nicki Minaj for selfies "so 'trash,' it's self-mockery. On that level, the selfie is decadence for a totally decadent era."
Kennel said self-portraits are as old as photography itself.
The National Gallery's current exhibition of the work of Charles Marville features selfies of the 19th century French photographer in which he styles himself as a suave Parisian boulevardier the hipster of his day.
Meanwhile, in London, the National Portrait Gallery has just put out a call for selfies to be included in a panel discussion on January 16 entitled "The Curated Ego: What Makes a Good Selfie?"
In announcing the event, organizers identified Russian Grand Duchess Anastasia as "one of the first teenagers to take a selfie." That was in 1914, when she was 13. Alas, she had no Facebook or Twitter account to share it on.