The National Party is facing a long string of unanswerable 'what ifs' that will plague it for some time.
What if they had not rolled Simon Bridges? What if Todd Muller had lasted? What if all those senior MPs had not quit?
There is absolutely no point in dwelling on 'what ifs' – but it is also hard not to, even for the most philosophical of beings.
The trouble with 'what ifs' is that they tend to become a festering sore. That is especially the case for those with a vested interest in them - who think they know the answer.
It will take some effort for them to try to put that behind them.
Arriving at Parliament on Tuesday, raw emotion prevailed among many MPs.
The target of the wrath was whoever leaked an email that MP Denise Lee had sent to the caucus in the second to last week of the campaign, objecting to an Auckland Council policy announcement.
MPs were calling for the leaker to be hunted down, and even kicked out of caucus.
Of course, it is also possible the leaker was among those publicly swearing vengeance on the leaker.
Collins herself is responsible for some of that rage, having said the day after the election that the party's internal polling dropped by five points in the wake of Lee's email surfacing.
At first it seemed an attempt to direct anger at the leaker, rather than her.
But Collins' wider goal was also clear: she wanted the leaking and backstabbing to halt, and one way was to make the cost of ill-discipline clear. The best way to do that was to get the other MPs to make that clear. The leaker will now know just how angry those who lost their jobs were.
But Collins now needs to try to dampen caucus rage.
At the time, Collins confronted an MP she believed had leaked it. That person is said to have strongly denied it.
However, by the time of an interview with the Herald on Monday, Collins was sounding caution about witch hunts and has rejected any suggestion she is still trying to find out who leaked it.
She is right to be cautious. The hunt for a leak can be more debilitating than the leak itself.
It drags out controversy, and builds resentment in caucus. Often such inquiries cast up nothing but more suspicion.
Collins knows this, having herself been accused of leaks without evidence of it.
"We need to be able to trust each other," she said, an acknowledgment that trust is a two-way street.
The example she used was of former National MP Jami-Lee Ross. After an inquiry, Simon Bridges finger-pointed Ross for leaking against him (Ross has denied it).
The fallout of that was more dramatic than is normally the case. But it also illustrates the dangers of such exercises. It has a massive effect on trust in a caucus.
The leak was not helpful, but National's results were down to much more than that.
As one MP put it, Covid-19 was always going to harm the party's chances but it could have withstood that better if its brand had not already been battered.
The glut of conscience issues over the past term also did not help party unity. National is a 'broad church' – but strongly-held personal views on issues such as abortion and euthanasia took their toll between the pews. It will be a relief those issues were largely resolved over the last term.
Some of what that review will uncover will be self-evident. Collins herself has already identified some of it.
First, National had a relatively solid offering of policies. It just didn't talk about them enough.
There were firm programmes in areas in which Labour was offering little that was new, such as law and order, education and the plan for the first 1000 days of a child's life.
Collins' leadership and the campaign strategy will also come under scrutiny.
Collins has the backing of the caucus, at least for now. She was thrown in as leader with a short run-up and against a strong head-wind. MPs believe she campaigned well.
That is what differentiates National's 2020 outcome from Labour's similar result under David Cunliffe in 2014.
That does not mean she will have their support until the next election.
She will need to try not to overreact to criticism, or gloss over questions that are raised about her own role.
The real value of the review is that it is a release valve.
It provides a mechanism for MPs and those who are no longer MPs to release steam out of the public eye.
Some of the more junior MPs saw the review as an opportunity as much as a post-mortem.
Throughout the Key era, National operated on the model of 'if it ain't broke, don't fix it.'
It is now clearly broke, and the MPs who are the party's future get a chance to have a say in the re-fit.
The priority will be to get it done as fast as possible, while still ensuring it is comprehensive and everybody feels they were listened to.
National cannot afford to give up a year to lick its wounds if it is to stand any chance of looking like an alternative government in 2023.