During the leader's speech at the SDLP conference, a fire alarm started screaming - it had apparently been touched off by cigarette smoke. Most speakers would have been cowed into silence by the loud and incessant noise, but not John Hume.
Raising his voice only slightly, he continued his message. The incident was a metaphor for his entire political career. Since he first took to the streets of Derry in the cause of civil rights, there have been many alarms, much screaming and a great deal of panic, but Mr Hume never deviated from his non-violent constitutional theme. Not so much soundbites as "Humebites", many of the familiar-sounding phrases were there. "We are a deeply divided people . . . the futility of political and sectarian violence . . . any dispute can be settled if the parties genuinely wish to do so."
Over the years, he has repeated them quietly and insistently, like a patient teacher with a recalcitrant class. Now perhaps he is on the verge of success.
As Mr Hume pointed out, the SDLP was born out of the civil rights movement. In words reminiscent of Martin Luther King, he claimed that "we have never been so close to the realisation of our dream".
One might continue the civil rights analogy and compare the SDLP to the National Association for the Advancement of Coloured People. Like the NAACP, it has won gains and concessions for its people without straying from the non-violent road.
It is a commonplace that the party's MPs and a good proportion of its activists are ageing. In a normal society, many of them would have a decade or more of government service under their belts. For some, the current talks process is a last chance at power.
But even if the talks result in an agreement, there will still be huge problems to resolve. This was a theme touched on by the party's deputy leader, Seamus Mallon.
For instance, the massive sectarian imbalance in the composition of the police force will take years to correct, quite apart from the issue of the nationalist community's allegiance to such a force.
Mr Mallon also echoed some of the concerns expressed recently by Sinn Fein spokesmen about the high level of security force activity in places like south Armagh and west Belfast.
Mr Mallon spoke of the possibility that this would increase the "No" vote in a future referendum, but non-aligned observers are beginning to give more credence to the notion that there may be a "securocrat" agenda at work, aimed at heightening tensions within the republican movement.
In his chairman's address, Jonathan Stephenson appealed to Sinn Fein leaders to spell it out to their followers that a united Ireland was not "immediately attainable". But the problem at this stage is that nobody really knows what, if anything, is attainable between now and next May.
There is even some concern among moderate nationalists that, in its anxiety to secure an agreement, the British government will make only minimal demands on the unionists. There is worry, too, that a big bomb from one of the republican factions could allow the unionists to walk out of the talks altogether. The SDLP has had its internal problems, but it is one of the few parties at present, North or South, that is stable and placid. The fact that no election looms means there is no need to worry about the Sinn Fein threat for now. If an agreement is reached, elections to a new assembly are called and the IRA ceasefire is still in place, the possibility of a pact between the nationalist parties will inevitably arise.
Meanwhile, Northern nationalists are making significant political advances. One of them has just become President of Ireland: there seems to be mixed feelings in the SDLP about that. There is unalloyed pleasure that its own Alban Maginness has become Belfast's first nationalist lord mayor.
The overall mood of the conference was one of cautious optimism. In helping to set the agenda for the Stormont talks and talking the republican movement off the window-ledge of paramilitary violence, the SDLP has already achieved two of the principal reasons it was set up. It has also spearheaded the advance of the Catholic population in civil society in Northern Ireland.
Quoting Nelson Mandela, a speaker unwittingly gave an exposition of the party's basic philosophy: "The real question is not whether the system works but for whom it works."
Some purveyors of gloom and doom have suggested the party could be eclipsed by Sinn Fein in future years. Confronted by that suggestion, the former Northern Secretary, James Prior, asked: "What on earth would we do?" But if achieving democratic politics meant taking second place to another nationalist party, one suspects many SDLP people would feel they had got a good bargain.