The magic words were "future" and "forward-looking". The AIB group chief executive used them seven times in his prepared statement to the Committee of Public Accounts, and umpteen times under questioning thereafter.
Mr Tom Mulcahy clung to the terms - describing the non-retrospective nature of the bank's 1991 understanding with the Revenue Commissioners - as though his life depended on them.
He sounded like the hero of the yet-to-be-made film sequel, Speed 3, a time-travel thriller in which an international banking group finds itself hurtling headlong into the future, knowing that if the speedometer drops below the year 1991, a massive tax bomb will blow up under it.
And as he gripped the sweaty throttle of AIB's forward-looking relationship with the Revenue, there was no doubt who Mr Mulcahy wanted cast in the role of the mad bomber.
The £100 million potential exposure highlighted by the bank's former internal auditor, Mr Tony Spollen, was "seriously unreliable," the chief executive said. "Seriously, seriously unreliable," he repeated, in case we didn't grasp how unreliable he meant. Then the bank's head of taxation, Mr Philip Brennan, weighed in with a description of how the £100 million figure came about, which to the layman sounded like: "take a number, double it, multiply it by your weight in grammes". When he finished, he said: "As you can see, that's very scientific". He meant this humorously, but it didn't get a laugh. Everyone was just too amused already at the inability of the State's foremost banking group even to guess how much DIRT tax it might owe, if retrospection ever came to pass. Each member of the committee had a go at teasing a figure out of them, but from the tortured expressions of the AIB officials they might as well have been asking them to calculate the average annual tax take from a pin-head full of angels.
The AIB's other favourite word yesterday was "uplift". This was the term used to describe the increased DIRT yield from the bogus accounts after the year of looking forward.
But poor Pat Rabbitte was confused: "Uplift? I always thought that was either a religious experience or a woman's garment."
Like everyone else, Pat was struggling to take in the great heaving cleavage that had arisen between the bank's account of the deal and that of the Revenue Commissioners on Tuesday.
In fact, the only thing everyone agreed about yesterday was that during the late 1980s, DIRT tax had caused the greatest symbolic exodus from the State since the Flight of the Wild Geese.
"There was a legitimate fear of a flight of funds," confirmed Mr Mulcahy, explaining the background to the 1991 reforms.
A former government minister had spoken of the need to entice back funds which had "flown the economy", he added, and another avian metaphor was just begging to be born. "Dirtbirds" was the only way to describe these flying fund-owners; but not even Pat Rabbitte thought of that one.
