When it was time, the former kitchen hand would head to the men's toilet.
Inside one of the cubicles, he waited anxiously while his colleague poured the contents of the crystal-like substance onto a "sampan" made of aluminium foil. After lighting up the crystals, he inhaled the white smoke using a straw.
"That's how it was almost every other day before I was caught," said Mr Muhammad, a 22-year-old part-time student.
"After one session of 'sejuk' (slang for Ice or methamphetamine in Malay), I suddenly had this abundance of energy to last the work day."
Mr Muhammad, however, is no longer taking drugs. He has been clean since last year, after completing his sentence at the Drug Rehabilitation Centre (DRC).
But the ex-addict felt so compelled to tell his tale that he turned up at The New Paper office last month with his tutor.
His biggest concern? That the drug is still so available to him that he can easily fall back into a dizzying spell of self-destruction.
Said Mr Muhammad: "If I want to score some Ice right now, I just need to make one phone call. It's as easy as buying a movie ticket."
While his stint in the DRC in 2012 was "quite sobering", he said that temptation still exists. His last job was at a catering company, which he said is a "hive" of drug activity.
Said Mr Muhammad, who was 20 when he was taught to smoke Ice by a 17-year-old: "I realised that I didn't want to be a part of that lifestyle any more, so I resigned."
He experimented with Ice because he could not cope with school and part-time work simultaneously.
After a full day in school, he had barely enough energy to perform his work duties. Yet, he needed the cash badly as he did not receive any allowance from his parents.
"The first few times, my colleagues said I could smoke for free," said Mr Muhammad.
"Later, because I wanted more, I found myself spending what I earned at work to buy Ice."
It cost him between $30 and $50 for 0.1g of Ice.
The high would remain for at least five hours and often left him with insomnia.
Buying "a set", which was cheaper at about 5g for up to $570, was something he could not afford.
"It's popular among my young colleagues because there's no telltale smell," Mr Muhammad said.
Yet, the physical signs were there. A security guard at work had commented that Mr Muhammad constantly fidgeted with his tongue and became restless after his toilet breaks.
After his release from the drug rehabilitation programme, Mr Muhammad said he would choose his work days to coincide with the Ice suppliers' rest days. Or he would volunteer to make food delivery rounds.
"If I didn't see them, then there would be less chance of me going back to Ice," said Mr Muhammad, who declined to name his former work place.
The woman who accompanied Mr Muhammad to TNP said she was his tuition teacher.
Declining to be named, she said: "I'm a mother, and after seeing what Muhammad went through, no mother would want their children to have easy access to drugs, particularly Ice."
She said she first noticed a change in his behaviour about two years ago, when he was tardy with his assignments and got angry easily whenever she confronted him about his school work.
Mr Muhammad's parents, who both hold blue-collar jobs, could not understand why his school grades were declining. Arguments with them broke out constantly when they demanded to learn the truth from him. His room was always his avenue for escape.
"When he finally explained he was abusing Ice, I knew I had to step in," said the tutor.
Unfortunately, it was too late. Mr Muhammad was nabbed in a drug raid at a pub in 2012.
He said: "By that time, I had lost good friends because they were tired of giving me the same advice."
His friends avoided him because their meeting would usually be an excuse for Mr Muhammad to borrow money to buy Ice.
"I looked in the mirror and I didn't recognise the face I was seeing," he said while pointing to his sunken eyes and gaunt appearance.
"I had become somebody else. But now that I'm clean (from drugs), I want to start over and gain my parents' trust again."
Get The New Paper for more stories.