Imminent danger forces us to look afresh at what we normally take for granted.
But there is also a risk that having spent so long walking in the shadow of dread, we have become almost comfortable with it, too comfortable perhaps.
We have momentarily gained a little respite from the spread of the coronavirus, but nothing could be more reckless than allowing a limited degree of success go to our heads.
Unintentionally sinking into familiar patterns, in the mistaken belief we are safe, risks losing the limited edge we have gained in keeping it at bay.
Given the endlessly shifting horizons of the pandemic, it would be foolhardy to believe that any progress is secure - or that any level of success is permanent.
That is why news of slippage in people's behaviour is alarming.
More concerning still would be any slackening in government reflexes in reacting to the threat.
We know to our cost how the virus goes from a spark to wildfire in days.
So to learn from the Department of Justice that it has only been in a position to make 60pc to 70pc of follow-up calls to passengers arriving into the State to check up on their 14-day quarantine, due to a rise in the number of passengers arriving, is deeply disquieting.
If more than a third of calls to passengers contacted in follow-up calls go unanswered, we may be wilfully reopening the door to a remorseless killer.
It ought not be possible for any returning passengers to escape the net, or evade protocols for the protection of public health.
If they need to be tightened, or sanctions made more severe, there must be no delay in doing so.
According to the Taoiseach Department's Liz Canavan, "complacency is our greatest enemy".
So it is. But appropriate State defences must be in place to make sure comprehensive tracking can take place immediately.
There is nothing random about the way the virus strikes, it is an ever-present danger until a vaccine is developed, swooping on any weak link in the chain. We have seen how one gathering alone was responsible for 20 new cases here.
The funeral of Bobby Storey in the North also showed how mass assemblies, for any reason, can present serious health challenges.
And given the worrying increase in overseas travel, and accelerated re-emergence of the disease in the US and parts of the UK, we must be more cautious, not less.
On Monday, the travel industry appealed to the Government to clarify the situation on travel. Yesterday, the Consumers' Association made a similar call.
They have appealed for compensation for people who must cancel holidays.
It would certainly be a lot cheaper to refund people left out of pocket after cancelling holidays than to have to confront the incalculable cost in lives that could be lost should a second wave of the virus strike as a result of returning holidaymakers.
We won't get a second opportunity to keep safe.