He underwent emergency surgery on Monday and then had a second operation, sources said, adding there was a likelihood of permanent damage that could leave him in a vegetative state.

Shyy told the crowd that the institution would investigate the incident and ask police for an explanation, including an allegation that officers had delayed an ambulance crew attempting to reach Chow.

But his remarks failed to appease the students who said no investigation was needed as the details of the case had been reported in the media and urged him to condemn police brutality over the incident immediately.

Shyy, who attended with other senior management officials, gave a short speech before he was stopped from leaving as emotional students fired off a lengthy list of questions, keeping the president at the meeting for more than five hours.

He and his colleagues promised the university would try to collect security camera footage from the car park after getting the consent of Chow’s family.

They would also seek the ambulance records from the Fire Services Department. He arrived at the gathering at about 6.20pm and planned to leave after about 30 minutes. He finally left shortly after midnight after managing to get into his car.

Some in the crowd became agitated by a woman, in her 30s, who was accused of taking close-up photographs. She was surrounded and had to show them all the pictures in her mobile phone.

The Fire Services Department on Tuesday rejected suggestions police had delayed the emergency services’ arrival on scene.

A spokesman said the ambulance service was called at 1.11am on Monday, but the crew twice encountered road blockages. It reached the patient at 1.30am before taking him to hospital at 1.41am.

“In the entire rescue operation, our rescue workers were not obstructed by police or any other people,” the department said.

Meanwhile, Link Reit, which owns the Tseung Kwan O car park, said it had looked at CCTV footage of the time around the incident but the camera, which rotates as it operates, did not capture the moment the student fell. The camera was also partly blocked by parked vehicles, it said.

A spokesman said that all the CCTV footage from that night would be kept and the company would cooperate with a police investigation, adding that if the student’s family or anyone they authorised wanted to look at the footage it would provide help.

HKUST was one of several universities that struggled to deal with the arrests and injuries of their students in the wake of the weekend’s violence.

Police said since last Friday and the weekend, they arrested 325 people – 247 men and 78 women – aged between 14 and 59 for an assortment of offences, from unlawful assembly to assaulting police and possession of arms and offensive weapons.

Over the course of Saturday and Sunday, police fired 423 rounds of tear gas, 140 rubber bullets, 11 beanbag rounds and 23 sponge-tipped rounds, said Senior Superintendent Kong Wing-cheung of police’s public relations branch.

The HKUST student’s fall happened during a confrontation between police and protesters which began on Sunday night, and saw more than 200 people still in the Tseung Kwan O district at around 2am. Protesters set fires and built barricades on roads, prompting police to fire tear gas to disperse the crowds.

A medical source said there was a chance the student could enter a vegetative state. “His critical stage is not over yet,” the source said.

According to local media reports, the student fell between floors of the Kwong Ming Court car park, and was seen running away from tear gas before the incident.

But a student union officer at HKUST said the cause of the fall was not known. The union was gathering video footage and photographs to try and determine why the man fell, external vice-president Vincent Ng Yat-ming said.

Chow was taken to Queen Elizabeth Hospital in Yau Ma Tei. Wei Shyy visited Chow on Monday morning for about 30 minutes, and in a statement the university said it “attached great importance” to the incident and would provide help to the student and his family.

Chow studies computer science at the university, according to Lai Wai-chun, provisional president of HKUST student union.

Meanwhile, a third-year Baptist University journalism student, surnamed Tang, was arrested at around 9pm on Sunday when covering protests in Taikoo Shing. Baptist University’s student union editorial board said he was wearing his press card and Hong Kong Journalists Association membership card when he was arrested.

It said Tang had not taken part in any frontline protest activities.

University president Roland Chin Tai-hong said in a letter to students and alumni he felt “heavy hearted” by the incident as the institution had been “liaising with the relevant government agencies” to seek “fair and proper treatment” for other students arrested over the weekend.

The university was deeply concerned about the well-being of the journalism student and had contacted his parents, he said, as a lawyer was sent to provide legal assistance, and teachers, including the journalism department’s head, had already been to the police station.

The university’s School of Communication and journalism department said in a statement they “strongly urged” police to treat Tang fairly, and called on officers to “respect the rights of student reporters and ensure their safety when they are performing their duties”.

Separately, Shue Yan University deputy president Hu Fai-chung said the school would write to the police commissioner to demand full details about a student who volunteered as a first aider, and suffered burns after being hit by a tear-gas canister in Wan Chai on Saturday.

The psychology and counselling student, known as “S”, is a qualified St John Ambulance first aider.

Hu said the university would ask for information on the incident so as to “clarify the situation”, according to an email sent to the whole school.

He said violence had been commonly seen in protests, and arrests and dispersal by police often resulted in injuries to protesters.

Hu visited S early on Monday morning in Queen Mary Hospital in Pok Fu Lam, and said the student’s condition was stable. He said S was being helped by lawyers and medical professionals.

More than 100 students and alumni gathered outside Po Leung Kuk Tang Yuk Tien College in Tuen Mun on Monday morning, where S graduated. They demanded the school principal condemn police violence.

A Form Four pupil surnamed Leung read out an official statement from students that asked school authorities to condemn police brutality, and called for a show of support for S.

“S is so young. He was only there to offer help amid the chaos,” Leung said.

The statement said students would boycott classes if authorities did not give a “reasonable response”.

A volunteer first aider, who saw the incident, said the canister landed between S’s backpack and back, “which is why he suffered such severe burns”.

“He was conscious even though he was suffering from third-degree burns,” said the volunteer, who only wished to be known as “L”.

Speaking on behalf of S, he said the injured student was disappointed with how “the police force has turned its back on citizens”.

L added: “S used to respect the police force for helping the community, but after witnessing brutality in the protests, he feels very upset.”

The school issued a statement online on Sunday, and said the principal and teachers had visited him in hospital and “we send our sincere concern for him”. The secondary school also denounced violence and appealed to students and alumni to stay away from danger.

Three Chinese University medical students were also arrested on Saturday during protests, according to the student union’s medical society.

The society urged university management to respond to the incident in a statement on Monday, as it also demanded police treat those in custody “humanely and with basic legal rights provided to them”.

Chinese University’s faculty of medicine expressed concern for the students, and said it had approached their families and would provide any help as needed.

At S.K.H. Lam Kau Mow Secondary School in Sha Tin, where three pupils were arrested during Saturday’s protests in Wan Chai, more than 100 students formed a human chain outside the school on Monday morning to show support for the trio.

Principal Ho Wai-ling said legal support had been provided to the trio, but the school was still trying to find out exactly what happened when they were arrested.

The students would not be expelled or penalised as they would already have to face legal procedures, Ho said, adding the matter would be brought to the school council later this month for discussion.

Additional reporting by Danny Mok, Christy Leung and Alvin Lum