But the bystander grabbed his shoulders from behind, pushed Rahi to the ground, and pressed his foot on to his face to try to restrain him.
The bystander grabbed Rahi's dropped bag and ran back to the store with it. Rahi ran off after he retrieved his knife from the ground.
The summary of facts also states that on February 16, Rahi drove around the town centre wearing his Mongrel Mob patch, grey pants and black shoes and then robbed the Four Square.
Just before he entered the store, he also donned a hooded high-visibility jacket over his clothing and disguised his face with a scarf.
Armed with a knife and carrying a bag, Rahi demanded cash and cigarettes from the store worker, who was loading cigarettes into a cabinet at the counter.
The store worker placed $700 from the till and five packets of menthol cigarettes into Rahi's bag, and Rahi ran out of the store and drove away.
On February 21, Rahi rode his pushbike around the Ōpōtiki town centre, and also played the pokie machines at Slims Bar before he robbed the Ōpōtiki Hotel.
A disguised Rahi brandished a large pair of scissors at the lone female worker behind the bar at the hotel and demanded cash.
After she put about $5000 from the till into his bag, Rahi fled on his pushbike.
Rahi was sentenced in the Tauranga District Court on Tuesday by Judge Thomas Ingram after earlier pleading guilty to three counts of aggravated robbery, one of aggravated assault and two charges of driving while forbidden.
Judge Ingram told Rahi that clearly the robberies were "planned and premeditated" to obtain money to feed his significant methamphetamine addiction.
Nothing other than a prison sentence could be imposed for this type of offending, and a stern deterrent sentence was required, he said.
Judge Ingram said the sentence start point must be eight and a half years' prison but he was able to take into account personal factors.
This included Rahi's cultural background report, which detailed a "tougher and significantly more deprived upbringing" than most people.
Judge Ingram also took into account Rahi's guilty pleas, his remorse letters and the considerable efforts he had made to rehabilitate himself while in custody.
"It is fair to say, Mr Rahi, that I'm not easily impressed, but you have impressed me.
"You asked that no convictions be entered until you had finished some [rehabilitation] courses you had started while on remand and have done so.
"This is not a common response. It shows me you are genuinely trying to free yourself from the addiction that has blighted your life for several years."
Judge Ingram also took into account that Rahi claimed he was no longer a Mongrel Mob member.
"I am also told that you have withdrawn from any involvement with the gang. This is again no minor matter as it will mean a considerably more difficult time for you in prison."
Judge Ingram said he was satisfied that Rahi had done everything in his power to show that he was genuinely remorseful and committed to turning his life around.
The judge sentenced Rahi to five years' prison.
Judge Ingram urged Rahi to remain "steadfast" in his stated withdrawal from the gang, as it would be a significant factor to his credit when the Parole Board decided his release from prison.