Over the next five to 10 minutes the cleaner would be subject to a terrifying ordeal, during which he was ordered to lie on the ground, had the shotgun pointed at his head and was repeatedly told "don't move or I'll blow your head off".

When the robbers noticed the cleaner had a ring on his finger they ordered him to hand it over.

"No, I can't get it off it's too tight," the cleaner said.

"We'll take your finger," Solomon Kifooti, now 23, who was armed with the gun, said menacingly.

But it was Jonah Taufua, now 22, a massive young man, who was responsible for the worst of the violence, repeatedly smashing the cleaner in the head, back and hands with the baseball bat, an attack acknowledged by his barrister Rob Hussey on Wednesday as being "gratuitous and unnecessary".

It was Taufua's upbringing and background of "extreme deprivation and disadvantage" that predisposed him to violence, Mr Hussey said, a factor that loomed large in the sentence process.

Taufua, who was born in jail and at 22 is at serious risk of institutionalisation, pleaded guilty to armed robbery and was jailed for a maximum of six years and nine months, with a non-parole period of four years and three months on Wednesday.

Kifooti was sentenced in July to a maximum of six years and nine months, with a non-parole period of four years and six months.

While Adam Potoczko, who was armed with the samurai sword, was jailed for a maximum of five years and six months, with a non-parole period of three years and nine months.

The cleaner arrived at the Greta Workers Club about 4.20am on December 22, 2018, locked the front doors and went to work. At 5.10am he saw a reflection of a figure that he thought was the greenkeeper.

But the three men smashed their way in, bashed him and ransacked the club.