Tony Abbott fronted reporters in Parliament House on Monday 20 minutes later than expected, but nobody minded.

The delay was caused by an emergency meeting of federal cabinet's National Security Committee – the first of what would be two NSC meetings the Prime Minister would chair that day.

With events still unclear, Abbott's public comments were measured, appropriately brief.

Australians, he said, should be vigilant, but they should also go about their lives as normal.

Operational questions regarding the Martin Place emergency would be dealt with by others such as the NSW Police.

No contact had been made with the perpetrator so it certainly was not for a political leader in Canberra to be giving out details of the siege or worse, speculating on such things as motive, or the number of hostages.

A security incident such as this is what security agencies had feared which is why ASIO had recommended Australia's terror alert level be elevated from medium to high in October.

Yet it was always acknowledged that "lone wolf" attacks – if that is what this incident was – are extremely difficult to detect because they come from blue sky and may involve no coordination. Intelligence, the front line in counter-terrorism, can be blind in such circumstances with no communications to intercept.

Monday was meant to be about another major issue of moment in Canberra – the release of the government's budget snapshot known as the mid-year economic and fiscal outlook.

It loomed as a big negative story for the government with major revenue write-downs smashing its hand-on-heart budget promises of a near-balance within four years.

While the Sydney siege raised the question of delaying MYEFO, Abbott and Treasurer Joe Hockey went ahead with it.

A cynic might say it was the ideal time to release bad news – when it would be guaranteed the least prominent placement in newspapers and bulletins.

This is a tried and tested trick by governments of all stripes. Yet proceeding with MYEFO on this occasion was also the correct call. The Prime Minister can hardly have called on Australians to remain unbowed by terrorism while grinding the business of government to a halt in Canberra.

Many aspects of the statement were already in circulation in any event so getting the rest out made sense – even if the statement itself will leave many Australians confused.

Consider its cross currents. Jobs growth is running at thrice the rate of last year but jobs and confidence remain delicately poised – so delicately in fact that a fiscally hardline government has suddenly gone all neo-Keynesian, using the deficit as a cyclical shock absorber for falling revenue rather than cutting spending to suit.

Even an iron-clad surplus promise, is now, as Labor's Chris Bowen unkindly noted, off on the "never-never".

But that's an argument for another day.