Ryan Taylor, 28, walked up to the automatic sliding doors of the Caltex service station in Kaleen, just after they were locked by the attendant on the night of August 24 last year.

Taylor waited to be let in, and then walked to the counter, buying a pack of Tally-Ho with exact change.

But, instead of leaving the store, Taylor stood in the doorway, preventing the sliding doors from closing and automatically locking.

He stood there for some time, taking off each shoe and putting it back on, all the while keeping the doors open.

Within 30 seconds, his accomplice Leigh Coulter, 24, sprinted into the store, brandishing a cross bar tyre iron.

Coulter - who has already been sentenced to three years and six months' jail for his role in the crime - jumped the counter and demanded the attendant open the till.

The worker complied, and then retreated as far away from Coulter as possible.

But, once he had grabbed a bundle of notes, Coulter began hitting the victim in the head with the tyre iron.

When he lost grip of the tyre iron, he punched him in the head instead.

The bashing left the victim with cuts to the back of his neck, and bruising and swelling to his right eyebrow.

The victim was taken to the Canberra Hospital and treated for his injuries.

It is understood the victim was an international student, who has since left Australia to return home.

As the bashing was happening, Taylor continued to stand in the doorway, without attempting to intervene or run away from the scene.

A passer-by, who was walking his dog, noticed the robbery, and ran inside to intervene.

He chased Coulter from the store, and struggled with him outside. CCTV vision shows the passer-by getting the best of Coulter, and chasing him from the scene. At one point, the man appeared to whip the robber with his dog leash as he fled.

Most of the stolen money was recovered.

Taylor walked off after offering to help the passer-by find his dog, which had run away.

The court heard that Taylor had drug and alcohol problems and suffered depression.

Justice John Burns criticised the 28-year-old's ''utterly naive'' belief that he could control his drug habit without help.

Justice Burns said Taylor's guilty plea entitled him to a discount to his sentence, and noted that he was not the principal offender in the robbery.

But the court heard that Taylor's role was significant, and that without him the crime could not have occurred.

He was sentenced to two years and four months' jail, and will be eligible for parole in February 2015.