The diminutive nun was in a towering rage.
"People have travelled a long way to hear him," she spluttered, gesturing to the crestfallen crowd behind her.
But all to no avail.
The hall was already bursting to capacity, and none of the latecomers had a prayer of getting past the implacable gatekeeper.
The Archbishop of Dublin, it transpires, is serious box office.
It was day two of the Eucharistic Congress in the RDS and it was standing-room only in the large hall for the speech by Dr Diarmuid Martin, titled, 'The Church in Modern Ireland'.
Every seat in the room was occupied by predominantly older pilgrims and plenty of clerics.
But the organisers had underestimated the star power of Dr Martin and eventually had to put the full-house signs up.
Not that anyone was expecting any razzmatazz -- that's not the style of this particular prelate.
Instead he delivered a considered, low-key address of the evolution of the modern church and its relationship with the State -- a relationship which has been tested in recent times by the Taoiseach's devastating Cloyne Report speech in the Dail last summer and also by the closure of the Irish embassy in the Vatican.
However, Dr Martin wasn't about to start a scrap between church and State during a congress promoting reconciliation, and made only an oblique reference to how the secularisation of politics in Ireland has changed the role of the church: "There are indeed those who prefer to see the church totally banished to the margins of the public square."
He discussed how to find a new way of evangelisation to re-engage with the disillusioned members of the faith.
"The Gospel must be preached courageously, even if it doesn't seem to find roots immediately in people's hearts," he said.
"Resignation and keeping things ticking over will never renew the church -- a divided and squabbling church will not attract young people but only alienate them".
Beside him on the stage, the papal legate Cardinal Marc Ouellet was listening intently.
The two men have been colleagues for many years, and Cardinal Ouellet is tipped to take over as head of the Congregation for the Doctrine of the Faith -- a powerful position within the Vatican which was previously held by Cardinal Joseph Ratzinger, now Pope Benedict XIV.
There was prolonged applause for Dr Martin's speech, but the busy archbishop couldn't stay to soak up the approbation of the audience as he hurried off for his daily press briefing.
He and Cardinal Ouellet strolled through the sunshine, with Dr Martin recognised and greeted every few steps by groups of pilgrims.
One pilgrim, Daniel Walsh from Belfast who is now living in London, was keen to shake the archbishop's hand.
"Diarmuid Martin has been a voice of honesty during all the dark times over the abuse scandals," he explained.
"Any time the hierarchy close ranks he's prepared to stick his neck out and tell it like it is, and so people trust him."
In the press briefing room, Dr Martin held a joint press conference with Anglican archbishop Michael Jackson.
"Relations between the churches are extremely good here in Ireland," Dr Martin pointed out, a view echoed by his guest. "I think our relationship is increasingly instinctive and I treasure that and want to thank him for it," said Archbishop Jackson.
One journalist from a Catholic paper began a question, "Your Grace . . ." before the Anglican prelate inquired good-humouredly, "which Grace?"
The reporter was the only one in the room who wasn't amused.
"The authentic Grace," he replied snippily.
Dr Martin defended the relatively low turnout at the opening Mass on Sunday.
'There are people who buy a seven-day ticket and they may not be here every day, but I thought that we had a good start on the first day and it was a ceremony that impressed everybody," he said.
And it did seem as if the glorious weather had brought a large crowd to the RDS, as more events got under way.
In the adjacent Simmonscourt building, a new exhibit had just opened -- a life-sized replica of the biblical village of Capernaum.
The entire 1,000sqm exhibit, complete with gravel road, house fronts, plants and a giant projection screen was constructed from scratch by professional set builders and then assembled in the RDS in a mere three days.
Faith, it seems, can move more than mountains.