She had stepped off the bus to retrieve her daughter's artwork which had fallen on the ground while they were queueing at the interchange.
But before Madam Sabrina Ng could re-board the bus, its doors closed and the bus moved off with her frightened three-year-old daughter still on board.
"I was shocked. I couldn't run after the bus so I went to the control station and explained the situation," said the 30-year-old who works in human resources.
Madam Ng was reunited with her daughter after 40 minutes of panic and hysteria.
Madam Ng and her daughter, Sara, had boarded SBS bus service 241 at Boon Lay Interchange at about 7pm on Feb 4 to take them home to Jurong West Street 92, which is about 10 stops away.
The bus was not crowded and they sat near the front of the bus.
But just as the bus driver started the engine, Sara told her mother that her artwork that she had done in class had fallen on the ground where they had been queueing.
Madam Ng told Sara to wait in the bus while she went to retrieve it.
"I asked the bus driver if he could open the doors as my daughter had dropped something just outside. I saw that he was Chinese so I spoke to him in Mandarin," she said.
Madam Ng claimed that from the driver's facial expression, "he was not happy" and "looked reluctant" to open the door, but he eventually did so.
Madam Ng stepped out to retrieve Sara's belongings, but before she could board the bus again, it started to move off.
Panicking, Madam Ng went to the control station, where they managed to track down the bus and confirm that her daughter was on board.
She called her father-in-law, who lives nearby, to go to the bus stop they usually alight at and wait for Sara.
"Thankfully, she was still on the bus and my father-in-law took her home," she said.
Twenty days later, Madam Ng is still angry.
She said: "I'm upset and furious because anything could have happened to my daughter while she was alone.
"That period of waiting and not knowing really got to me. She (Sara) was crying the whole journey."
Madam Ng said she filed a complaint about the incident two days later.
In her letter of complaint, she also mentioned that while she was explaining her situation at the control station, another driver "made an insensitive comment", referring to her as "a mother who does not know how to take care of her young".
Ms Tammy Tan, senior vice-president of corporate communications at SBS Transit, said they are sorry to learn of Madam Ng's distress.
Investigations revealed that the bus captain was unaware that Madam Ng's child was on board as there was another commuter seated next to her and no one had informed him about it, she said.
Said Ms Tan: "It was only after the bus had left the interchange that a commuter came forward to inform him that the child was on the bus while the mother had alighted."
She added that the bus captain then "immediately" contacted the Operations Control Centre for assistance.
While the bus was on its way to drop her daughter off at the bus stop where her relative was waiting, the female commuter sitting next to the child assured and comforted her.
On the bus driver who made the insensitive comment, Ms Tan said: "We agree that this was not done in good taste and will be taking disciplinary action against him. We apologise for any distress caused."
This article was first published on Feb 25, 2015.
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