Fans display the South Korean flag as South Korea team members celebrate winning their women’s semifinal curling match against Japan on Friday. (Natacha Pisarenko/AP)

They crossed the border on a diplomatic and sporting mission — almost 300 North Koreans, coming into the South — and yet so much of their experience felt like a mystery.

Some of the North Koreans spent their nights here in isolation on a docked cruise ship. A team of red-suited cheerleaders showed up at hockey games, singing with fixed smiles. The North’s athletes, when they spoke at all, said things like, “We are very happy,” and, “There have been no inconveniences whatsoever.” And not once did they address the deeper questions about their experience — one in which, for the purpose of political unity, they had stepped into a world nearly opposite from their own.

But then, on the third-to-last day of these Games, a different group of people from the North showed up at the Olympics. They were defectors, 20 of them, and they’d taken a bus earlier Friday from Seoul, their adopted home. They’d come here as part of a choir group, performing at a crowded train station, but after they were done singing, they headed across town to an arena — the site of a women’s curling semifinal match between South Korea and Japan — where they showed an usher their tickets, marked Section 202.

“This way,” she said, pointing to the right, and then a much different North Korean experience at the Olympics began.

Some of the defectors, arriving before the match, saw the long ice sheets down below and took selfies. Some giggled. Another gasped. One defector, Park Soo-Hyang, 27, said she’d been bingeing on curling recently — learning the rules online, memorizing the South Korean team’s roster, watching the team’s matches on her smartphone.

“So psyched,” she said, holding her ticket, walking up to her seat. Twenty minutes later, when South Korea took an early lead, a cheer that started in Section 202 spread across the whole arena.

“Dae-Han Min-gook!” Clap, clap, clap, clap. “Dae-Han Min-gook!”

South Korea! South Korea!

But it was there, in that section, where the feelings about these so-called Peace Olympics were perhaps most complex. The defectors weren’t perfect proxies for the North Korean athletic delegation — only the Pyongyang elite are chosen to represent the country abroad — but still they knew the feeling, both exhilarating and alienating, of arriving in the South. They knew what it was like to go from one country, repressive and family-run, to another, wired and democratic and relatively free. They could imagine what the North Korean athletes and cheerleaders were thinking, standing there, with their poker faces.

“I feel sorry for them,” one defector said.

“I think they must be shocked,” another said.

“They must feel like birds in a cage,” said Kim Ga-young, 28, who left North Korea six years ago. “I think they would be in pain, seeing the outside but not being able to fly out.”

The defectors, more so than most younger South Koreans, want to see the two Koreas unify. During their choir performance — they sang with 22 people born in the South — they chose songs with peace and unity themes. As they see it, unification is sensible. Most have family members still in the North. Unification would undo the messiest parts of their lives.

And yet, adjusting from one Korea to the other is its own perilous task. Over dinner, before the curling match, one defector, Kim Il-hyeok, 22, said he had been picked on in high school after he arrived. Often, he struggled to understand the South Korean language, which had evolved from the North’s version by incorporating foreign words. Kim Ga-young said she’d been living in the South for five years. She sometimes thought she had fully assimilated, and then she’d realize in a jolt — seeing the way a woman dresses, or the way a man flirts — that she was still accustomed to a less accepting and more conservative society.

“I lived the first 23 years of my life in a socialist state,” she said.

Park, who defected nine years ago, said she now feels almost fully South Korean. Her nails are painted a glittery red. She wears the kind of long black parka that is popular this winter season in Seoul. She is a senior college student majoring in social welfare. But still, something stirs in her when she sees the North Korean flag. “It’s a bit complex,” she said.

“I guess a lot of South Koreans, when they think of the North, they think of Kim Jong Un and nuclear weapons,” she said. “But I have lived in North Korea. I can’t hate North Korean people.”

But now, in front of her, there was curling to watch, and one section below, near the ice, the flags that were waving were South Korean ones. Park settled into her seat as the match moved along. The arena was mostly hushed, with bursts of shouting, but the crowd was into it. So was Park. She talked about the match with the people next to her. At one point, she took out her phone and posted a photo to Instagram, tagging it #awesome and #womenssemifinals, adding a gold medal emoji.

Then, the match came down to a final stone, a spot in the final on the line.

“Shhhh,” several people in the defectors’ section said, and Park took out her camera to record the last moments of the match — South Korea’s final throw, in a tied game.

Down on the ice, the curling stone glided toward the bull’s-eye-like house. It slowed. It slowed some more. There was frantic sweeping. The stone stopped, perfectly placed, for the game-winning South Korean point, and Park held her hand over her heart. The defectors, like everybody else, were out of their seats now, standing, clapping, for what had just become a signature moment in this host country’s Winter Olympics. “Great!” Park said, no longer holding her camera, just cheering, looking at the packed arena, not really caring that there was still a three-hour bus ride back to Seoul. One last time, a chant spread from section to section — “South Korea! South Korea!” — and this time, it was impossible to tell where in the crowd it had started.

Yoonjung Seo contributed to this report.