A man pressed a blanket over the mouth and face of his girlfriend to calm her down when she became hysterical after they had both taken methamphetamine, or Ice.
Jackson Lim Hou Peng, 41, was worried that her shouts would make neighbours call the police.
The Singaporean odd-job labourer ended up suffocating Tran Cam Ny, 32, a Vietnamese KTV lounge performer and hostess, on the morning of Nov 20, 2014.
Yesterday, Lim was sentenced to a total of 9.5 years' jail and three strokes of the cane after he pleaded guilty to one count of culpable homicide without intention to cause death and one count of taking Ice.
He was sentenced to 4.5 years for the homicide charge and five years' jail and three strokes of the cane for the drug charge, which is the minimum for third-time abusers.
In sentencing Lim, Justice Tay Yong Kwang said: "This case demonstrates how taking illegal drugs can sometimes lead to very sad and fatal consequences which were never intended."
The High Court judge advised Lim not to go back to drugs again after he is released from prison.
The court heard that Lim and Ms Tran were in a relationship while married to other people.
On the night of Nov 19, 2014, Ms Tran stayed over at Lim's rental flat in Ang Mo Kio and called two friends to join them. Lim started smoking Ice and she joined him.
Not long after, she started crying and quarrelling with Lim. He left the bedroom to take more Ice but she continued berating him.
The couple exchanged blows before they were separated by her friends, who pulled her into the room.
When she continued shouting hysterically, Lim went into the room and hit her.
At this point, her friends left the flat.
Ms Tran did not stop shouting even after Lim pinned her down and hit her so he pressed a blanket over her mouth and face with both hands.
After she became motionless, he called his father and a friend for help before dialling the emergency hotline.
While waiting for paramedics, he tried to resuscitate Ms Tran but failed.
She was pronounced dead at the scene and Lim was arrested.
An autopsy found that she suffocated to death. Bruises were also found all over her body.
Toxicology tests found amphetamine and methamphetamine in her system.
Lim also suffered superficial abrasions. A urine test showed he took methamphetamine.
His lawyer, Jennifer Lim, urged the court not to impose more than four years for culpable homicide as his actions were not premeditated.
Deputy Public Prosecutor Lee Zu Zhao sought at least six years for culpable homicide, arguing that Lim cannot say he was provoked as he had a choice not to enter the room to engage Ms Tran.
The maximum punishment for culpable homicide without intention to cause death is 10 years' jail, caning and a fine.