She was preparing ingredients and chatting with helpers at her yong tau foo stall on Monday morning when she heard a crashing sound at the back of the coffee shop at the foot of Block 116 Lorong 2 Toa Payoh.
"All of us were frightened," the stall owner, who wanted to be known only as Mrs Teo, 52, was quoted as saying in Mandarin in The New Paper.
"I thought someone had fallen from the building or that there was a car accident," she added.
Mrs Teo and her two workers quickly went to check and found that a window panel had come crashing to the ground, right behind her stall.
No one was injured in the incident, which occurred at 7.30am.
Chinese daily Lianhe Wanbao reported on Monday that the window panel fell from an eighth-storey unit in the block, narrowly missing Mr Hu Lai Fu, 78, a worker at the coffee shop's roasted meat stall.
Mr Hu told Wanbao in Mandarin: "I had just gone to the back to get a pail.
"The window could have hit me. It was a really close shave."
Both Mr Hu and Mrs Teo said it was not the first time this had happened, and Mrs Teo told TNP that it was lucky neither Mr Hu nor her employees were hit.
"If it had hit someone, wouldn't it be terrible?" Mrs Teo said.
Wanbao reported that the eighth-storey flat was being rented out. It quoted a tenant, who declined to be named, as saying that she had opened the sliding window in the kitchen and was shocked when one of its panels fell.
When TNP visited the flat on Monday afternoon, the tenant said she had called the police to report the incident but declined to comment further.
The Building and Construction Authority website states that home owners are responsible for checking and maintaining their windows regularly. They may be held liable if one breaks and falls.