SINGAPORE - More details and photos are emerging of the incident in a cinema at Nex shopping mall on Sunday (Aug 30) afternoon that left two women injured when a ventilation duct fell from the ceiling.

Nineteen-year-old Sebastian Koo was watching the movie Tenet at the cinema hall 6 with his four male friends when he heard a strange crumbling noise coming from the ceiling at about 4.30pm.

"It was in the middle of an intense fight scene, so I thought it was just an extremely realistic sound effect," said the full-time national serviceman.

But dust began to fall from the ceiling as it cracked open and, without warning, the ventilation duct fell to the floor about two rows behind him, bringing plaster debris from the ceiling along with it.

Thankfully, the ventilation duct, which was large enough to cover at least four seats, had not hit anyone, he noted.

Though he narrowly averted the debris by swiftly ducking down and bracing to cover his neck, Mr Koo said he was alarmed to see that a large chunk of plaster debris had struck a woman's head.

She was seated just one row behind him.

Having been part of the Red Cross Youth in secondary school, Mr Koo, who is trained in first aid, immediately attended to the woman.

"She was lying in a foetal position and clutching her head, but I don't think I saw any bleeding and she was conscious," said Mr Koo, adding that the cinema staff offered her a cup of water and she was soon able to sit up.

"I asked if she was okay and she was able to respond to my questions, though she complained that her head was very painful," he added.

The woman was one of two victims who were taken to Tan Tock Seng Hospital for their injuries.

The Straits Times understands that she is likely to have suffered from internal head injuries, while another woman suffered minor bruises and has been discharged.

A spokesman for Tan Tock Seng Hospital declined to respond to queries on the patients' conditions and the severity of their injuries, citing confidentiality.

Though two of his friends had minor scrapes from the debris hitting their heads, Mr Koo said that all of them were able to quickly "snap out of it" and leap into action.

One of the men called the Singapore Civil Defence Force (SCDF), while the other two helped to ensure that everyone evacuated the cinema hall, and no one was trapped underneath the debris.

"It was very instinctual for me to quickly snap out of my state of shock and make sure that everyone was okay. I was so afraid that I was not able to help those around me," he said.

In photos posted on website Mustsharenews, the dislodged unit can be seen lying across several cinema seats.

Other images show Singapore Civil Defence Force (SCDF) rescuers and paramedics attending to the injured. One patron can be seen lying on the floor, while another is on a stretcher.

All the cinema halls were later evacuated, with staff noting the names and contact details of patrons for their tickets to be refunded.

A Shaw Theatres spokesman said on Sunday (Aug 31) that the duct was dislodged at around 4.45pm. He added that theatre staff attended to the injured customers until paramedics arrived.

"Our priority is to provide support to our injured patrons," said the spokesman, adding that the company is working with landlord Gold Ridge and the authorities to investigate the incident.

ST understands that the Nex building is co-owned by Gold Ridge and Mercatus.

However, a spokesman from Nex said that its management is unable to share more information and that it is still working with the authorities and Shaw Theatres on the incident.

A Building and Construction Authority (BCA) spokesman said on Sunday evening (Aug 31) that one if its engineers was sent to investigate the incident at 6.30pm.

In the meantime, Shaw Theatres at Nex has been instructed to close its cinemas pending further investigation.

"BCA has also instructed the building owner to appoint a professional engineer to carry out a detailed investigation of the incident, inspect and assess the condition of the other ducts in the cinema, as well as recommend rectification measures to be carried out by the building owner," the spokesman added.