Two of the three female mall employees who witnessed a mother plunge through the floor panel of an escalator in China had experienced a close shave just minutes earlier, new surveillance footage has shown.

The incident last weekend - which made international headlines - in a shopping mall in Hubei's Jingzhou city had cost 30-year-old Xiang Liujuan her life.

The housewife managed to thrust her son out of harm's way after the floor beneath them collapsed, but she was dragged into the gaping hole by the escalator's machinery.

China's state broadcaster CCTV released a two-minute video that captures how a female mall employee had travelled down the escalator from the seventh to the sixth floor.

She reportedly forgot something and took the escalator back up to join a colleague waiting at the top of the escalator.

The same floor panel beneath the pair then gave way slightly, causing them to nearly lose their balance.

Instead of turning off the escalator, however, they purportedly left to notify the mall's management before returning.

The footage also showed one of them prodding the panel with her foot.

Less than a minute later, Ms Xiang and her son got on the escalator, with the two staff members pointing at the panel to warn them as they approached the top.

Ms Xiang can be seen picking up her son while still on the escalator, and quickly pushing him to safety when the panel caved in.

It took rescuers over four hours to cut through the escalator and recover her body. 

The tragedy has cast an unfavourable spotlight on China's safety standards, with criticism also levelled at a maintenance crew which forgot to screw down the panel after repairs.

Netizens are also blaming the two female employees for not turning off the escalator's mechanism or stationing themselves at the bottom to warn off shoppers.

Hubei has issued a province-wide ban on the use of elevators and escalators by the Shenlong Elevator Company, which made the escalator in the mall.

A video released on social media on Tuesday revealed the extent of paranoia that has gripped escalator users in the country - many have been caught on camera avoiding stepping on floor panels at the top.