The Northern Bank robbers got away with more than the £26m police said was taken in the raid, one of the bank hostages has said.
Mr Ward said the robbers threatened to kill his family
Chris Ward said he had no second thought about putting his family's lives first.
The bank official from Poleglass on the outskirts of west Belfast said the armed gang had threatened to kill them.
The PSNI said £26.5m was taken in the raid on the Northern Bank headquarters in Belfast on 20 December.
On Monday, the Northern Ireland secretary and the Irish foreign minister said they were 100% convinced the IRA was involved in the robbery.
It follows an assessment by PSNI Chief Constable Hugh Orde blaming the paramilitary group.
In an interview for BBC's Spotlight, Mr Ward said it was staggering how much the gang knew about him and his bank colleague Kevin McMullan.
"Later Kevin was talking to me and I was talking to Kevin about things that they did say about us, that they knew about us," he said.
"It was just terrifying... even the fact that they knew I was involved in Celtic (football club), they knew where I lived, they knew my family, they knew my family's names - they knew about my brother and his girlfriend.
"You are walking up the street now and you are wondering - 'Is someone watching me?'"
The first gang member he encountered gained entry by saying he was a Celtic fan and wanted to talk about something connected to the supporters club, of which Mr Ward is secretary.
He was taken to a three door car outside his house and told to lie on the floor in the back of the vehicle.
Mr Ward said: "So I lay down in this car and the driver pointed a gun at me.
"As soon as I seen the gun my head just turned towards the seat, because I panicked."
Mr Ward said he was "totally terrified".
The gang said that he would be in the car for a "wee while" so it was best that he did not move or say anything.
He was later transferred to a second car in which he was brought to the home of assistant manager Kevin McMullan in Loughinisland, County Down.
They were told what to do the next morning and how to react when they went to work.
The gang gave the employees mobile phones and ordered them to keep in touch.
At that point Mr McMullan's wife had been removed from the house by the robbers and the Ward family were being held hostage in Poleglass.
Mr Ward said the robbers threatened to kill his family if their instructions were not followed.
They then had to go to work as normal at 1200 (GMT). They travelled together by car, but then entered the Northern Bank separately.
"You had to act as if nothing was wrong... it was very difficult to do. But you knew in the back of your head that you had to do it - that you couldn't tell anybody.
"If you phoned this confidential helpline that the bank say you have to, your family were gone - that's the reality of this.
"It's all well and good - and no disrespect to the bank - to say if you are ever kidnapped you never ever pay out, you phone this confidential helpline.
"That is a 'Superman' story - what is going to happen? Is Superman going to fly through your window and beat these men up and save your family? This is serious, serious reality stuff.
"There was no way in the world that I ever thought once of putting my family's lives at risk for the sake of a bank."
Dressed in uniforms
In the afternoon, Mr McMullan sent home a messenger and three other staff in the bank's cash centre before 1800 GMT, leaving both him and Mr Ward alone.
Mr Ward was ordered to take part in the dummy run in which more than £1.2m was taken out of the bank in a sports bag.
"I just walked out of the bank and that was it, with over £1m in my bag."
When Mr Ward returned, he and Mr McMullan contacted security guards to say they were loading up rubbish to hand over to a removal firm.
They then filled green transportable boxes with cash and delivered them to the gang at 1845 GMT.
Two of the robbers were dressed in the uniforms of a delivery service firm and wore wigs and hats.
The gang made a first run and the two bank employees were told they had 15 minutes to reload.
After the gang left, the two employees left the bank at about 2100 GMT and travelled to Loughinisland.
Spotlight will be screened on BBC One Northern Ireland at 2315 GMT on Tuesday.