You get the feeling that if you really prodded Sean O'Brien, he just might explode.
The memory of that match is still so raw, searing deep into his consciousness, filling him with so much regret that only recompense can amend his state of mind.
And so you gently probe once more. And still he struggles. "I don't want to talk about it," he says sternly.
For him, Tullow's disconsolate derby defeat to Carlow a fortnight ago has been cast aside, especially that final scrum five which Carlow somehow won against the head in the expiring minutes.
O'Brien was amongst the 1,000 or more in a breathless Oak Park watching helplessly as his side lost a game that possessed more fervour than many a Pro12 fixture.
He knows the players intimately. Until last summer, he coached them, before handing over the reins to former Leinster hooker Bernard Jackman. And he still helps out when he can.
Tullow's slow start this season was arguably due to a clutch of O'Brien's first-team players deciding to follow him on his World Cup adventure.
That's something else he's been trying to forget right there: the World Cup. So long ago and yet so vividly relevant.
The more Wales disappeared into the rearview mirror of his memory, the closer the Six Nations rematch loomed into his consciousness.
"Yeah, I suppose it's good that we have them first up," he says laconically. "They're probably one of the form sides, through the World Cup and now coming into this competition, so it will be nice to have them at home and nice to have them to start off the Six Nations."
Reviving that quarter-final against Wales in Wellington, a truly missed opportunity in his brief international life story, remains a sensitive issue.
"It doesn't go away, you're right. It is something that is in the back of every individual's mind and obviously there was a lot of hurt after that game," he says.
"But this is a different competition, a different year, so we have to re-group, re-focus and not let that match get the better of us, and stick to what we want to do this time around. It's as simple as it gets."
That may be a tacit acceptance that Ireland's tactics were horribly askew in Wellington. Or that, as Ronan O'Gara outlined uncomplicatedly this week, revenge is irrelevant, for it cannot repair the damage.
Either way, the match had to be consigned to history. Eventually.
"That one nipped away at me for a while. I'm usually pretty good at that -- forget about it and move on to the next game -- but in fairness, for a week or two after that you were kind of kicking yourself saying, 'I could have done this or I could have done that'.
"Obviously at that level, the quarter-final of a World Cup, you never want to lose or play badly, and we did. As an individual I'd say everyone kicked themselves over it. But it's a new year now; leave it, it's gone, we have to move on."
Watching Wales in the semi-final stung.
"Well, I watched that game and my thought on it was that if Sam Warburton hadn't been put off that day, Wales would have beaten France. In fairness to them they played good rugby in the World Cup and they're a dangerous side -- we're going to have to front up big time."
The accusation that Ireland were outmanoeuvred mentally, as well as physically, still rankles.
After all, surely Wales' tactic of double-tackling Ireland's back-row, particularly numbing the influence of the European Player of the Year, was hardly akin to splitting the atom?
That said, Ireland did seem unwilling or unable to alter their approach.
"I don't know if we were too predictable," demurs O'Brien, keen not to stray from the official narrative. "We had our chances to score, I had one myself. And we put a bit of pressure on them in the second half as well, but our concentration wasn't good at times and we let them in for a couple of soft scores.
"We did break them down at times but in fairness they did play well and they shut us down effectively. They bring a lot of energy in everything they do but they're a physical side as well.
"They are tough lads. First and foremost the physicality will have to be there from us and we have to sort out our ruck.
"They slowed up our ball a lot in that previous match and that's one area we have to sort out to get us on the front foot."
The pressure for revenge may not feature in public discussion; privately, Declan Kidney's itinerant Munster mantra, that declares 'you'll never beat us twice', will be unveiled at least once next week.
For O'Brien, the pressure is predominantly internal.
"I don't think there is any more pressure on us but I think as a group, the rugby we played at times previously, we want to reach that level again and go beyond it.
"We should be putting ourselves under pressure to play more consistent rugby and to push ourselves beyond where we've got to before. We can't afford to be less than 100pc.
"That showed in the World Cup. We had a couple of opportunities and didn't take them, we made a couple of mistakes as well and they punished us.
"They're that type of team; they can do that to you. We have to be on the ball, simple as that. It's a good game to have at the start because we can see where we really are after that.
"In that aspect everyone really wants to go out and win this championship. Hopefully we'll take a step towards that with our first game."
Last year's stand-out Six Nations and Heineken Cup performer has been relatively cowed of late; Wales and Montpellier before Christmas demonstrated how to reduce his effectiveness.
Subtly, he has engineered a different side to his game. He still wants to blast holes but he knows the brute force won't always suffice.
"Obviously it's harder," he says, referring to the expectations built up after his extraordinary impact on world rugby in 2011.
"You are targeted a bit more but it's up to me to try and maintain a high standard and bring different aspects of my game into play. That's what I'm trying to do."
Europe watch out. O'Brien may be just ready to erupt.