The North Koreans at the Olympics have been unfailingly polite. Hounded by cameras and pestered with incessant questions, athletes and cheer squads alike have smiled and occasionally uttered a few pleasantries. Even the stern minders have stood at a distance, making sure never to show an intemperate face to the world.
It took only a fraction of a second on the ice to tatter that image, after what looked like a dirty tripping attempt by a North Korean skater.
On Tuesday night, Jong Kwang-bom lined up for the men's 500-metre short track race. He took the inside position as North Korean cheerleaders waved their country's flag in perfect unison. Jong was the last of the North Korean athletes to compete at the Games.
The starter pistol sounded.
Jong skated forward, but almost immediately dug in his right toe. He fell, tumbling hands first onto the ice. As he began to slide, his right arm swept outward, landing on the front of the skate next to him, which belonged to Japan's Keita Watanabe. Jong's hand moved backward with Watanabe's left foot, and the Japanese skater stumbled.
At first, no one quite knew what to say. Judges called for a restart. Watanabe was gracious. "I believe it was unintentional," he said. "His hand happened to be by my skate as he fell down."
Then the Internet took over. A short clip of the first race began to circulate, and viewers were convinced the tripping attempt was intentional.
Was he "showing off his skill by blocking Japan?" wondered one Korean writer on social media. "He looked like someone who was ordered to trip up the Japanese short tracker," another wrote.
Japan is the former colonial occupier of the Korean peninsula, and Pyongyang has sought to exploit that shared history during the Olympics in an attempt to create division between Seoul and Washington. Was this part of that strategy? Or did Watanabe just happen to be the closest skater to the flailing North Korean?
"Japan is always the easy 'card' for North Korea to play and if that means taking out a Japanese skater to help South Korea, so be it," said J. Berkshire Miller, a senior visiting fellow at the Japan Institute of International Affairs.
Only days before, Olympic spectators had been swept up in a heartwarming moment in which Japanese skater Nao Kodaira defeated and then consoled a crying South Korean Lee Sang-hwa, the defending champion.
Then came the disastrous short track race, the latest example of the trouble South Korea courted when it invited its northern neighbour to the Games. (Jong, like many of the North Korean athletes, did not formally qualify for the Olympics; the International Olympic Committee made exceptions to allow their participation.)
"This type of incident will only heighten feelings of mistrust towards North Korea in Japan – which already is lined in deep-seated suspicion as a result of the abductions issue and the current missile and nuclear crisis," Miller said.
It didn't much help, either, with the harmonious look North Korea has been trying to present at the Olympics.
"Pyongyang is interested in projecting the image of a responsible, normal nation at this time. Sportspeople to some extent are inevitably ambassadors for their country, so this won't help," said Andray Abrahamian, a visiting fellow at Pacific Forum CSIS, an arm of the Center for Strategic and International Studies.
Deliberately tripping an opponent is unusual in short track, but not unheard of.
"If this is remembered, it may harm the DPRK's image, but probably not too badly," he said, using the formal name for North Korea.
"It depends how we choose to see it. Like with Ryan Lochte's arrest at the Rio Games: global viewers could choose to think ill of him and his teammates, or that Americans were liars and scumbags. It depends what you'd like to see."
But figuring out what, exactly, happened at the short track arena was complicated by the fact it wasn't just once.
On the second start to their heat, Jong and Watanabe again came into contact. As they entered the first corner, a moment that is always amongst the most fraught as skaters seek position, Watanabe began to turn inside. As he did, Jong reached out at him, the North Korean's hand moving toward the Japanese skater's chest.
Jong then batted away Watanabe's hand, only to lose his own balance, landing on his bottom and sliding off the track.
"Athlete Jong, you can't do that," said a shocked sportscaster on South Korea's KBS Television.
This was the North Korean's only race and it was over. Watanabe advanced to the next round, but judges disqualified Jong. He took no questions from waiting reporters.
With reporting by Eunice Kim