CCTV shows one patron approaching the armed man with his hands in the air, before the robber fires a warning shot into the ceiling and kicks the man to the ground.
Detective Sergeant James Bolton said the robbers used an "extreme level of violence", and it could easily have been a much worse outcome.
"A few inches lower and it could have been a homicide."
As one of the robbers ran from the pub to the getaway car, another member of the public tried to stop him, before he was tackled to the ground and stomped on.
Another patron can be seen in the footage grabbing a bar stool and approaching the men, before a second warning shot is fired into the ceiling.
The armed man is seen pointing the gun directly at terrified patrons of the bar.
The robbers are then seen getting into the white Subaru parked outside, where a third suspect was waiting.
Bolton said the car was originally stolen from Sunnyhaven Ave that evening, and dumped in Roseberry Ave half an hour after the robbery.
Police now believe the robbers used a second getaway vehicle, a light blue or grey sedan.
CCTV footage showed it travelling along Waipa St nearby before the robbery in convoy with the white Subaru.
Not long after it was dumped, the same grey/blue sedan was seen travelling on Waipa St nearby
"We believe the suspects got into that vehicle," Bolton said.
A victim of the robbery, whose name and face is obscured in a Police 10/7 video, said the ordeal had created "a lot of anxiety and nightmares" for staff, who had been doing group counselling sessions.
"I didn't realise until I was face-to-face with them. It all kind of set in when I had to give them the money."
The first male has been described as male Māori or Polynesian, about 1.8m tall with dark clothing and carrying a long barrel shotgun.
Police described the second man as being of medium build, in dark clothing.
Anybody with relevant information was encouraged to call Police 10/7 on 0800 107 4636, and mention case number four.
