As biting darkness descended over Castle Buildings, Stormont, Mr Seamus Mallon's mood and demeanour reflected the sudden chill.
The former deputy first minister designate - whose own need of re-election could ironically spell another potent threat to the survival of the Belfast Agreement - would not pre-empt Senator George Mitchell's judgment call.
But he was impatient to have it. And the deputy leader of the SDLP was clear, for all the coded language, that the Mitchell judgment, when it came, would amount to one thing or the other. However the pill might be sweetened, he said, "either we succeed or we don't succeed."
For Mr Mallon, plainly, talk of a soft landing was precisely that - talk, for the optics, no more meaningful than the benign hope of recent weeks that the improved atmospherics between Sinn Fein and the Ulster Unionist Party pointed to an inevitable break in the impasse endangering the Good Friday accord. "Ambience isn't going to resolve the issue," he said, warning the UUP and Sinn Fein that the needs of their respective parties were transcended by the needs of the agreement itself.
Suddenly that ambience appeared somewhat changed. Senator Mitchell worked on into the night, his aides insisting he had no definite travel plans, and that no assumption should be made about the conclusion of his work this night, or even this weekend.
The senator, by all accounts, has a long-standing engagement in Belfast next Friday. Close participants in the process suggested he would build the opportunity around this to meet the British Prime Minister, Mr Tony Blair, and the Taoiseach, Mr Ahern, to report his conclusions.
So maybe no definitive conclusions for the moment - a possibility informed by the general appreciation that this "professional deal-maker" is the man least likely to emerge from Stormont to announce himself or his review a failure.
At this writing, speculation persisted that he might yet produce a plan - prescriptive in nature - giving the parties a period of some weeks for consideration. Some veterans of the review insisted the prescriptive approach, no matter how appealing, would prejudice the senator's role as independent chairman and facilitator. Others said it didn't matter in any event because "once he's out of here, he's gone." To which prediction was added the creeping notion that Mr Peter Mandelson, while urging the senator on, might actually be itching to take charge of the process himself.
What we do know is that - even as the serious engagement between Sinn Fein and the Ulster Unionists apparently continued throughout the day - Mr Trimble told his party executive there was no deal on the table. Moreover, he apparently repeated there would be no deal until and unless the republican movement committed to a process of decommissioning leading to total disarmament by May 2000.
Well-placed sources told The Irish Times earlier this week there was no evident disparity between the private and public positions of Sinn Fein. It seems equally clear there has been no deviation by the UUP from its "no guns, no government" policy. Nor has the UUP been any more prepared to accept Sinn Fein's assertion that it does not speak for, and cannot commit, the IRA.
At an earlier stage in this review some of the more junior members of Mr Trimble's Assembly team appeared impressed with Sinn Fein's progression along the democratic path. However, it is the
heavyweights like Mr Ken Maginnis - not for nothing sometimes referred to as "the Godfather of decommissioning" - whose counsels have prevailed.
Mr Trimble has been signalling for some time that he would look at the sequencing of events - provided he first secured a republican commitment to a decommissioning process to follow the timetables, schedules, and modalities prescribed by the international commission. This is widely taken to mean a willingness to see the prior creation of the executive - a move which would probably trigger some challenge to his leadership. But that commitment was integral to the entire concept of unionists and republicans jumping together. It is not, apparently, forthcoming, at any rate at this point.
Which leaves Senator Mitchell and the two governments to ponder how to build on an apparent advance in republican language and effect a soft landing - while stemming the seepage of credibility from the process itself, of which Mr Mallon warned last night.
Maybe the senator has some wondrous trick still to perform. Maybe he will call it a day, and give Mr Mandelson his turn. But whatever about that idle press speculation, one fancies that prospect will prompt a collective gulp inside the Northern Ireland Office. For Mr Mandelson will know - from Mr Mallon's words and his bearing - that resolving this crisis is not about to get any easier.