Hong Kong: Chief Executive Carrie Lam's first meeting with the Hong Kong public to discuss the long summer of protest had been carefully designed to elicit the true feelings of the supposed silent majority.

From 20,000 citizens who applied online to take part in her "dialogue platform", a computer randomly selected 150. And when 130 smartly dressed citizens arrived to take their seats before Lam on Thursday night, a host pulled tickets out of a drum, like a game show, to determine who would get three-minutes to speak.

Hundreds of pro-democracy protesters rallied near the venue where Hong Kong leader Carrie Lam met members of the public for a dialogue on Thursday.

As person after person stood and gave Lam a piece of their mind, it was soon clear it would have been more efficient for Lam to listen to the demands of 1 million streets protesters all those months earlier.

Before they spoke, Lam had said this was not a propaganda show and she fully understood the public was heartbroken and anxious. She said she would seek a way out for Hong Kong.

Strict security checks and a ban on gas masks and umbrellas inside the dark hall could not stop the sound of protesters chanting on the road outside drifting in.

For all the contrivance of the dialogue, staged at the Queen Elizabeth Stadium and televised live, the message on the streets was echoing what the Hong Kongers inside were saying.

The demand for an independent commission into alleged police brutality was raised repeatedly. The first questioner, a lady in a smart black suit jacket, raised the request.

The second questioner, wearing a face mask, also wanted an independent commission into police. Some officers had recently been caught on video kicking a yellow-vested church volunteer at a protest and tried to dodge responsibility by claiming it was a "yellow object" not a man. The yellow object's church disagreed.

"I work in a bank, I am in my 30s. I was not disappointed with the government or police three months ago but in the past three months I am deeply disappointed," she said, to big applause.

Protests raged outside the stadium that housed Carrie Lam's community dialogue event. Bloomberg

The third speaker worked at Hong Kong airport and said she felt the city was at risk of being subsumed into mainland China and losing out to nearby Shenzhen.

The fourth speaker, in a blue suit, repeated the protester's slogan: "Five demands, not one less." The 130 cheered.

Another woman in a mask said Hong Kong people had many questions about San Uk Ling detention centre on the Chinese border, where it was rumoured protesters were taken and beaten. This was why people wanted an independent police inquiry, she said.

The sixth speaker was among many who raised the July 21 Yuen Long incident, where it is alleged police stood back as triad gangs beat protesters and commuters in a train station. "Police are abusing their rights," he said.

Hong Kong Chief Executive Carrie Lam addresses a packed stadium during her community dialogue session. Getty Images

It was time for Lam, who had been taking notes, to talk. A giant digital clock counted down her three minutes.

Wearing a light grey checked jacket and black pants, Lam held the microphone with two hands and walked towards her audience. She said she was "quite moved" by her "six friends" who had spoken.

Nobody was above the law and she wouldn't tolerate police who abuse the law, she said.

Lam acknowledged the public was on a search for the truth of what happened inside Prince Edward mass transit railway station on August 31, when police ran through a train carriage beating passengers and protesters. She asked the public to wait for the police oversight body to finish its investigation before judging the outcome.

Chinese state media broadcaster CGTN cut its live webcast of the event 30 minutes in.

Within minutes, the next speaker had accused Lam of causing so much trouble for Hong Kong that Chinese President Xi Jinping wouldn't stand next to her for National Day. "You must step down!" she said.

Finally, the name of a "blue", or government supporter, was drawn from the barrel. She called for a crackdown on the media. Later, another woman called for a ban on politics in the classroom and compulsory Chinese history lessons for students as a cure.

From the 30 people allowed to speak four were supportive of the government or police.

A 26-year-old told Lam she should spend 15 minutes each day reading an online forum known as LIHKG and used by the protest movement to mobilise - if she wanted to understand young people.

The public dialogue was held just days out from China's National Day celebrations. Getty Images

He said he supported "One Country, Two Systems", the deal that guarantees Hong Kong special autonomy but acknowledges Chinese sovereignty. He said the accusation by Lam and Beijing that protesters were seeking independence was "a straw man".

The most significant development on Thursday night was Lam's commitment that the San Uk Ling detention centre would no longer be used to hold protesters, and what had occurred there would be investigated. Human rights investigators have so far been barred from entering.

But Lam also said Hong Kong's deal of One County, Two Systems was not the same as autonomy for Hong Kong. She repeated her line used to justify the police crackdown - that anyone who breaks the law must be held accountable.

After the dialogue ended, a familiar scene emerged: thousands of protesters blocked the road outside the stadium and chanted "Five demands, not one less".

Police stand guard during the community dialogue event. Bloomberg

Riot police stood inside the hall, where Lam waited out of view until 1.30am, unable to leave until four hours after the event finished. The government was fearful of the optics of firing tear gas to disperse the crowd on a night that was about talking, not violence.

As Lam had earlier driven to the event, school students in uniform had formed a human chain and held a banner from a nearby overpass.

Miss Lo, 17, clutching a toy of protest mascot Pepe the Frog, had summed up the evening before it began: "We want her to listen to our voice and talk about the police. There have been unreasonable cases and we see it all live on TV."