Kiwis waking up this morning in their first lockdown in over a year will be hoping it is short-lived - but there remain many reasons to be worried.
Chief among them is that there is no indication of any connection between the Devonport man and the border.
That means there could be untold links in the chain of transmission between him and whoever brought it into the country.
There are also already hundreds of contacts from the several indoor venues the man and his wife visited.
That includes back-to-back nights at a Coromandel pub with about 70 to 80 others per night.
The couple also partook in tourist activities, potentially with other out-of-town tourists who could have already taken Delta to other parts of the country.
This is why the lockdown is, and needs to be, nationwide.
For alert levels to be eased in three days' time, Prime Minister Jacinda Ardern will be looking for genomic sequencing results overnight to link the man's Covid to an existing case in MIQ.
That would give an indication of how much time the chain of transmission has been chugging along, and the size of the circle that needs to be contained.
While the man had been QR scanning, other people visiting the locations of interest may not have been, so Ardern will be hoping people are checking the information assiduously, and, if they are essential workers, isolating accordingly.
A surge in people with symptoms getting tested today - as well as wastewater testing around the country - will also paint a picture of how far and wide Delta has spread.
The wastewater results in Auckland last week were negative, suggesting there were no chains of transmission silently running through the community.
But even if all of these testing results in coming days indicates minimal spread, Delta only needs the smallest of footholds and a smattering of non-compliance with lockdown rules to go gangbusters.
We've seen that in Sydney, where the mere passing of strangers in public places has seen the virus spread - and continue to spread - for weeks despite lockdown-type restrictions.
That may already have happened here with the rush on supermarkets last night, leading to crowded and congested toilet paper aisles.
The importance of compliance is not lost on Ardern, who last night turned up the volume on the "Team of Five Million" rhetoric, imploring Kiwis to look after each other and come through once again.
Last week's announcement about how the borders might re-open next year is also an incentive to stay home for the next three days.
If Delta can't be kicked away, all those bets are off.
Not only that, but level 4 will likely be with us for far longer than three days.