Dr Tony Holohan dropped the bombshell public health advice into the lap of Government last Sunday, dispersing months of pent-up tension along with flying shrapnel.
The chief medical officer wrapped up the meeting of the National Public Health Emergency Team (Nphet) last Sunday evening with agreement from the 40-odd members on what to recommend to Government: an urgent move to the red-hot Level 5 restrictions to quell the rising spread of the virus.
The mood was grave, according to one informed source. As Dr Holohan later outlined in his letter to the health minister, disease modelling predicted up to 2,300 cases and 43 people admitted to hospital every day by November 7.
This called for the "proactive" and "robust" measure of a Level 5 shutdown for four weeks to suppress the virus. That meant mostly everything but schools and creches would shut and the 5km travel rule restored.
Not everyone at that meeting was convinced and some were taken by surprise. "Some people raised concerns about the level of political buy-in," said a source, which is exactly what came to pass.
Ultimately, Holohan won over the expert group but his advice was roundly rejected by a Government that three days earlier had been advised that everything could stay as it was.
Nphet's advice was based on science. But behind the science is a long and not so hot summer of discontent as the science structures that helped get the country through the first wave were dismantled.
In the Covid-19 lull, the Department of Health launched a review of Nphet and the plethora of subgroups that advise it. By the end of the review, only Nphet itself and the Irish epidemiological modelling group, chaired by Professor Philip Nolan, are still standing.
The Expert Advisory Group was subsumed into the health regulator, Hiqa. Subgroups such as those on acute hospitals, vulnerable people, nursing homes, and on behavioural research to gauge public buy-in on restrictions - were stood down, their work reassigned to other entities.
The biggest change was the Taoiseach's decision to set up a new group, chaired by Government Secretary General Martin Fraser, to effectively interrogate Nphet's advice before it goes to Government to weigh up how workable it is. Practical, yes. But as the former Fianna Fáil minister, Conor Lenihan, observed, it could hardly be a vote of confidence in Nphet.
One source, a member of one of those groups, told the Sunday Independent last month about concerns that had emerged between officials and civil servants in the Department of Health. There was a fear that the "pure" medical and scientific advice presented to Nphet was at risk of being coloured, diluted or filtered by being put through the civil service wringer before it reached Government.
And it was against this backdrop that Tony Holohan announced his return to the Covid-19 frontline - a decision that took some by surprise. He had stepped out three months earlier to care for his wife, Emer, who was receiving palliative care for a type of blood cancer, and their two teenage children. He was due to come back last Monday but in fact started work over the weekend, as Covid-19 figures surged to more than 600, prompting him to call the Nphet meeting for that Sunday.
"Apart from government ministers not expecting this, Martin Fraser and COG [the Covid-19 Oversight Group] were totally blindsided," said one source. "Martin Fraser is not a man to be crossed. He is the most senior civil servant in Government."
One health source asked, if the advice of moving to Level 5 was so urgent and necessary, why did Nphet not repeat it when the group met again on Thursday? Instead, Nphet recorded its mounting concerns but advised maintaining the status quo.
Professor Ivan Perry, a public health expert in University College Cork who sat on a now disbanded expert Covid subgroup on research, said public health is both a science and an art. Science is in understanding the disease, the art is in percolating that science into a workable public health policy to fight it. Tensions come with the territory.
The question is less who is in charge but who is right. For what it's worth, Prof Perry agrees with Dr Tony Holohan and Nphet: Ireland must move to Level 5.
"We have a very narrow window. Nobody is certain how it will go. It seems a necessary and sensible precautionary principle to do what we can now to limit the surge bearing down upon us."