In June, passengers on a high-speed train from China's financial hub Shanghai to Beijing failed to reach their destination.
Halfway to the capital, officials wearing protective clothing stopped the train, boarded and announced on megaphones that everyone must get off because one of the passengers had been linked to a Covid cluster.
Chinese people mostly went along with such demands early in the pandemic because they believed the government knew what it was doing. Now, the authorities can't rely on such compliance.
Travellers shouted back: "No! Why should we get off? How did you let this person on the train?"
But they were soon bussed off to an isolation centre hundreds of kilometres away.
Such measures are part of China's uncompromising "zero Covid" strategy. President Xi Jinping has repeatedly warned that no other path is acceptable.
After the initial outbreak in Wuhan, the country has been kept inside a giant Covid protection bubble, shielding the population from the high death rates experienced elsewhere, but it has come at a cost - and growing political risk.
In China, what the Communist Party fears above all else is major social unrest - and Mr Xi does not want to see this ahead of his move into a historic third term at a Party congress later this year.
A cloud of uncertainty
While the rest of the world is trying to live with Covid, China is the only major economy still prioritising the fight against the virus above almost everything else.
So-called zero Covid measures involve mass testing, tracking and strict isolation. Just a handful of cases can spark a city-wide lockdown.
Beijing has had only a few infections recently but its more than 21 million residents are required to queue for PCR tests every three days to access public buildings and even corner shops.
When a Covid case is confirmed, a whole suburb can be swiftly cordoned off. It's been especially hard for businesses - shops, bars and restaurants can be seen pulling down shutters for good.
Everyone in China is living under a cloud of uncertainty. It's difficult to make plans, and it makes one wonder how much longer people will put up with this.
If the Party is not worried about all this, it should be. It's not hard to imagine riots in Shanghai if residents were to be confined to their homes again.
Yet, China has shown no signs of shifting its Covid approach. The world is looking on and asking why.
In short, there are two reasons: politics and vaccines.
China's vaccine rates are still too low
It's not clear why China dropped the ball on vaccination rates, which are still seen as too low for the country to safely reopen. Officials fear that a widespread outbreak could overwhelm hospitals and cause many deaths.
"Some vulnerable groups haven't been fully vaccinated with two doses or booster shots, so we can't just give in," Professor Liang Wannian from China's National Health Commission said in March.
There's been a belated move to ramp up vaccine rates - 89% of people have had two shots, but only 56% of those eligible have received a booster, according to official data.
A few months ago, the situation was much worse.
It's been especially worrying among the elderly. In Hong Kong, a huge proportion of those who've died have been older and unvaccinated.
During the Shanghai outbreak in April, city officials said that only 38% of those over 60 had received three shots, and only 15% of those over 80 had got the first two jabs.
Across the country, only 19.7% of those over 80 have had a booster.
Why the reluctance? For many in China, the government's success in controlling Covid before the Omicron variant seems to have reduced the urgency for vaccination.
Officials had been portraying Covid as an overseas problem, blaming passengers from abroad for bringing the virus into China and this belief took hold.
People have also told the BBC that some doctors have warned those with underlying conditions of the dangers associated with vaccination - rather than of the dangers of not being vaccinated, especially for the elderly or patients in high-risk groups.
Pensioners the BBC spoke to in a Beijing park said they weren't too concerned by the virus.
"I'm not worried about Covid. Just be careful, wear a mask," one 85-year-old woman told us. She and her husband had just received a shot that morning, she said.
A man nearby said: "Covid management in Beijing is good. Beijing people, the Chinese people, listen to the government. Unlike people overseas, when asked to stay at home, we just stay at home."
But Beijing is yet to have a full shutdown, with people restricted to their homes, to the extent that Shanghai, Wuhan, Xian, Jilin and other cities have.
People in the capital often compare China's experience with what they think has happened abroad. State-controlled media reports heavily on Covid in other countries. But it has been much less inclined to accurately cover the chaos and hardship as residents suffering food shortages battled through the lockdown in Shanghai.
So why hasn't Mr Xi's administration pushed vaccines harder? PCR tests are required for travel - why not vaccination records? Several international business groups in China have called for some of the vast resources devoted to testing and quarantine to be reallocated to a more vigorous long-term vaccine strategy.
Earlier this week, the Beijing city government announced a change: proof of vaccination would be required to enter cinemas, gyms, internet cafes, libraries, museums and other entertainment venues. But, within days, state media has reported officials walking this back saying that it is not compulsory.
But vaccinations are only part of the issue.
Zero Covid has turned into a political challenge
A significant part of the problem seems to have started with officials having too much faith in the Party's propaganda.
Government representatives have openly ridiculed other countries for opening up. China would not do this, they declared.
In June, Mr Xi visited Wuhan, where the pandemic first started. State media said he stressed the value of the "dynamic zero Covid" approach and told locals the government would prioritise people and prioritise life. He was quoted as saying that, if China switched to a "herd immunity" approach, the aftermath would be unimaginable.
While the Omicron variant has shown how unstoppable the virus can be, the language from the top in China remains centred on "defeating" the virus and "winning the war against the pandemic".
As a result, many people here believe that, with enough effort, the virus can somehow be expunged.
If this crisis had been years away from the next Communist Party congress - which will usher in Mr Xi's third term - the mood might be different. But it is just months away.
Former leader Deng Xiaoping introduced a two-term limit to prevent the rise of another figure like Mao Zedong who ruled China for nearly three decades.
But that limit has now been dropped to allow Mr Xi to remain in power for as long as he chooses. It is not a small shift in the country's political history.
If there are those in the senior ranks who don't want Chairman Xi to go the way of Chairman Mao, there are not many ways to stop it, certainly not many opportunities.
What might be needed?
- a political vehicle (like a Party congress)
- an emergency (for example, an economy-smashing epidemic)
- the handling of that crisis to have been bungled
- for enough senior Party members to decide that the risk of keeping Mr Xi in power is greater than the risk of opposing him
It is hard to imagine that the last of those pre-conditions is anywhere near in place. But China's leader and his allies would always be considering the worst-case scenario to make sure it doesn't happen.
In May, the party's seven-man Politburo standing committee, which sits at the top of Chinese politics, stressed the need for the "resolute struggle against all distortions, doubts and denials of our epidemic prevention policy", according to the published highlights.
They would not have been discussing "doubts" about zero Covid if such wavering didn't exist. It must also have existed at a reasonably senior level.
Covid fatigue is everywhere
It would be surprising if questions were not being asked in the upper echelons of power. For generations, China's economy has been the most important priority and Covid is wrecking it.
Economists are speculating that the country's statistics are being massaged to hide the true impact of the virus and the approach to fighting it.
The World Bank predicted that China's real GDP growth would slow to 4.3% in 2022 in its June update, largely because of Omicron outbreaks and prolonged lockdowns.
But it's too late now to drop zero Covid before the Party congress. Mr Xi has to ride it out and hope for no more city-wide lockdowns before his new term.
In cities which have had multiple or long lockdowns, signs of Covid fatigue are everywhere.
More social media posts openly make fun of the government. In other countries this might not be unusual - in China, it represents a real shift. When Shanghai was shut down and food deliveries were not getting through, people started posting clips of the song - Do you hear the people sing? - from Les Miserables.
It doesn't mean the building of barricades is imminent, but it is a slap in the face for the government whose reputation for Covid management has gone from highly effective to bungling and inflexible.
Last week, when state media quoted Beijing's party secretary having said the zero Covid approach would remain in place for at least another five years, it prompted an instant outcry on social media.
There was a quick correction. Apparently there had been a misunderstanding.
An announcement followed that quarantine for international arrivals would be reduced to seven days in a hotel followed by three at home. Perhaps this was a way to ease jitters and show people the government is trying to relax restrictions.
But many believe China is simply kicking the can down the road - one day it's going to have to find a way forward.
A potential off-ramp could involve redefining zero Covid and finding a way to declare that victory has been achieved.
Until then, brush fires will keep appearing. The Party wouldn't want them to get out of control.