Chris Ward denies being the 'inside man' for the robbery
There was "a catalogue of security failures" at the Northern Bank's Belfast HQ at the time £26.5m was stolen, Belfast Crown court has heard.
A QC representing Chris Ward - who denies being the robbers' "inside man" - said panic buttons were not working and CCTV cameras were not recording.
He asked assistant manager Kevin McMullan, who was taken hostage, if he thought the defects helped the raiders.
He told the court information on the staff rota was the key to the raid.
"I didn't think of defects in security," he said.
"My thoughts in terms of information of this issue has always been that somebody within the cash centre provided that information."
A police interview conducted with Mr McMullan the day after the robbery was played to the court, where he tells a policewoman: "Something struck me as very strange.
"Whoever these guys are, they knew that myself and Chris were starting at 12 o'clock on the late shift that day (20 December).
"The decision was only made on lunch-time on Friday (17 December) as to who was working and they got that information from somebody.
"The robbery was based around our shifts and they knew it was me and Chris that they needed to take."
After the interview was played to the court, defence pointed out that the rota for the cash centre employees was pinned on the back wall of the department.
The lawyer also pointed out that other people including security staff, cleaners and contractors had access to the cash centre due, in part, to security defects.
The defects included main gate panic buttons not working from January, CCTV cameras at the bullion loading bay not recording and a fault with the entry system into the basement area of the bank, which housed the cash centre.
Mr Ward, 26, from Colinmill in the Poleglass area of Belfast has been charged with robbing the bank of £26.5m and of holding both Mr McMullan and his wife Kyran hostage. He denies all the charges.