A former Certis Cisco corporal yesterday received a shelling from a judge who found him guilty of performing a rash act in a game similar to Russian roulette.

Gregory Lai Kar Jun, 23, needlessly fired one round from his revolver on Aug 13, 2015.

District Judge Hamidah Ibrahim also found him guilty of intentionally obstructing the course of justice.

Lai hid the discharged round in a traffic wand and lied to a policeman about the incident the next day.

Said Judge Hamidah: "Lai had absolutely no justification in the first place, in the absence of any threat, to remove his revolver from its holster, place a single bullet in the chamber, put his finger on the trigger guard and fire it off twice."

Lai was on duty at Tuas Checkpoint with his then colleague, Muhammad Dzul Adhar Azmi, now 22, when he decided to play with his revolver.

He was issued 10 rounds in all - five in his revolver and another five in his speed loader, which he kept in his bullet pouch.

At around 2pm, Lai emptied his revolver and placed a bullet inside the chamber, which can hold five rounds.

Nothing happened the first time he pointed the weapon at the floor and squeezed the trigger.

However, when he squeezed the trigger again, it went off.

The two men then looked for the discharged round. Lai found part of it under a table about an hour later, and hid it inside the battery compartment of the traffic wand.

To cover up what had happened, he threw a second bullet in a toilet, then reported that he had lost two bullets there.

Dzul, who was also a Certis Cisco corporal at that time, threw the discharged round into Bedok Reservoir at around 2am on Aug 14.

He was jailed for three weeks and fined $2,000 on Oct 21 last year, after pleading guilty to obstructing the course of justice and failing to inform the police about Lai's rash act.

Yesterday, Judge Hamidah said Dzul was only about 1m away when Lai fired the round in a room that measured 2.7m by 1.7m. The bullet could have ricocheted anywhere within the room, she said.

"He must have been fully aware that squeezing the trigger of a loaded gun with another person in very close proximity was a highly risky act that could endanger human life," she added.

Lai is out on $15,000 bail. His lawyer Peter Ong Lip Cheng will present his mitigation plea on Feb 9.

For obstructing the course of justice, Lai can be jailed for up to seven years and fined. For performing the rash act, he can be jailed for up to six months and fined $2,500.