Until yesterday evening Sinn Féin had been carefully treading the thin line that saw it voice outrage at the scale of the RHI scandal yet refuse to lay blame at the feet of Arlene Foster, who as minister for enterprise oversaw the scheme that is forecast to cost Stormont £400m over the next 20 years.
While it left the party open to criticism, there was a general acknowledgement that condemning Mrs Foster would plunge the institutions into crisis. However, developments over the past 48 hours meant its tightrope strategy was no longer sustainable, as it would leave the party exposed to justifiable claims that it was going soft.
The potentially knock out blow was delivered in a velvet glove, in language that was measured rather than aggressive. Mr McGuinness ensured he played the ball rather than the man, so to speak.
His remarks are an interesting prelude to Monday's assembly debate where the SDLP has tabled a motion of no confidence in the DUP leader. The motion is destined to fall because it requires cross-community consent but if Sinn Féin votes with the opposition then Mrs Foster position becomes untenable.
Arguably, Mr McGuinness's call offers the most pragmatic route forward, providing an opportunity to reduce the relentless heat that threatens the combustion of the institutions. The suggestion that his Stormont Castle counterpart take a sabbatical has echoes of how Peter Robinson manouvered after the Irisgate scandal broke. Then there was a period when the first minister stepped aside and an independent investigation was carried out which ultimately vindicated him - albeit in a private report that was never made public and could never be scrutinised.
The difference with this scandal is that despite Mrs Foster's assertion that she can't be across "every jot and tittle", she is actually up to her oxters in the RHI and with potential for more revelations to come, it's possible that when she steps aside, it will be for good.
