She was among the first in her group to complete the trek up Mount Kinabalu on Friday at 7.15am.
But the earthquake struck soon after, sending rocks falling down.
"That's when everything started shaking," Amal Ashley Lim, 12, told Malaysian newspaper The Star.
A quick-thinking teacher pushed Ashley and her schoolmate under a shallow overhang as rocks rained down on her group.
They watched helplessly as some of her schoolmates were struck by the falling rocks.
While under the overhang, her friend burst into tears.
"I did my best to calm her," Ashley said.
Their teacher, who had gone looking for the others, did not return after 15 minutes.
Ashley shouted for help and their guide, Mr James Michael, heard her cries and led the duo to safety.
Ashley was among 29 pupils and eight teachers from Tanjong Katong Primary School who were on an overseas learning journey at Mount Kinabalu in Sabah.
Yesterday afternoon, Ashley returned to Singapore together with 18 pupils and two teachers.
It was a tearful reunion, with her exchanging hugs with her family members and friends.
Ashley's uncle, Mr Hafiz Ahmad, 43, was among a group of relatives seen at Changi Airport Terminal 2, outside the holding room for family members of the affected pupils and teachers.
He said the family was there because Ashley's mother, who was not identified, was there by herself. Her husband is overseas.
Mr Hafiz said: "One of the reasons Ashley is alive is because a teacher pushed her under an overhang.
"My niece is distraught right now. She suffered hypothermia. Other than that, there are no other serious injuries."
Ashley's grandmother, who declined to be identified, said Ashley is probably still traumatised by what happened.
She told The New Paper on Sunday in Malay: "She's still crying, because she saw her friends...
"Ashley waited for the helicopter at two different places because the helicopter could not land. She then descended with a guide."
She said that the teacher who helped her granddaughter was injured, with blood on her hands. According to her, this teacher is still in Sabah.
This article was first published on June 8, 2015.
Get The New Paper for more stories.