It was just after 6pm yesterday and the loud screeching sound instantly caught his attention.
Peering out of his office window, the executive, who wanted to be known only as Mr Tan, said he saw dozens of workers running away from a construction site at Mattar Road, off Aljunied Road, about 400m away.
To his horror, he noticed that a crane at the construction site had precariously tilted to its right. Mr Tan, who is in his 40s, told The New Paper: "The crane's boom was resting on a two-storey-high pillar at the site.
"If the crane had toppled over, its boom would have probably cut a nearby apartment building in half."
The crane had been hoisting a metal container when the incident happened.
Luckily, no injuries were reported.
Mr Samuel Liow, a resident of a nearby walk-up apartment, said he was informed of the incident at about 7pm as he was on his way home.
His six-unit apartment building is located next to the construction site, where a church is being rebuilt.
Work at the site began in January this year, residents said.
Mr Liow, 37, who is self-employed, told TNP: "I was surprised to see the crane leaning on its side. My immediate concern was my family's safety. Luckily, my unit is not in the crane's path."
At about 9pm, police ordered all the residents in his block to evacuate.
Together with a few other families, Mr Liow and his family took shelter at a nearby bus stop.
Mr Liow, who has three pre-school children, said he hoped that work to put the crane upright would not take too long.
Just after 9pm yesterday, two additional cranes were used to stabilise the affected crane from tilting further, witnesses told TNP.
The roads leading to the construction site were closed to traffic. Nevertheless, there were many passers-by who turned up to watch.
The Ministry of Manpower (MOM) confirmed that an incident had taken place at SCT Construction's worksite at Mattar Road.
MOM's Occupational Safety and Health Division has commenced investigations.
An MOM spokesman told TNP: "Preliminary findings indicate that a crawler crane had toppled on its side during lifting work. No one was injured in the incident."
All work at the site was ordered to stop yesterday.
When TNP checked with Mr Liow at 11.45pm, he said he had been told that the operation would take "another few hours".
"We have been booked into a hotel," he added.
This article was first published on April 6, 2016.
Get The New Paper for more stories.