Shortly after midnight three Saturdays ago, guests from a Kings Park wedding reception filed into taxis and chauffer-driven vans and made their way home.
Troy Buswell, who like most of the revellers had been drinking since 6pm, declined to do so, instead wandering off down a driveway and into the night.
When he called Colin Barnett on Sunday afternoon to offer his resignation, Mr Buswell could not explain his decision to get behind the wheel of his ministerial car, a white Holden Caprice, and drive.
"Troy stressed to me last night he is making no excuses whatsoever," the Premier said yesterday.
"He repeated that several times and he can provide no logical explanation for his behaviour."
The only reason the public knows what happened on that night is that a witness to his behaviour approached The West Australian and Seven News on Saturday to say what he saw.
The witness, who was driving with a friend down Roberts Road, Subiaco, and had to hit his brakes to avoid a collision, made a detailed call to police at 1.28am to describe the erratic driving of a white Holden Caprice.
Officers arrived at the Roberts Road address described by the witness within seven minutes, but by then the car was parked behind a high gate and there was no sign of its driver.
For reasons Police Commissioner Karl O'Callaghan and the Government could not explain yesterday, it did not show up as Mr Buswell's address in the police computer system.
The Caprice's licence plate was registered to the Office of State Administration.
Five minutes into a six-minute call, the witness, according to Mr O'Callaghan who listened to the tape of the call three times, said: "We actually joked between ourselves that we thought it looked like Troy Buswell."
That information was not deemed by the call-taker to be of a sufficient quality to pass on to the attending officers.
Judging that the immediate threat to public safety had passed, the officers moved on.
The Police Commissioner did not learn of the incident until alerted by Seven News on Sunday afternoon.
The day after the wedding, Mr Buswell's chief of staff Rachael Turnseck learnt her boss had suffered a breakdown.
It is understood she had some level of knowledge of the traffic accident involving Mr Buswell's car but that her priority was to get him urgent medical help.
The next morning, she met the Premier privately and told him about the breakdown.
She did not mention the car, which the Premier learnt about only after The West Australian's approach to Government figures set in train the timing of the Treasurer's resignation.
Mr Barnett admits he did not ask any questions of Ms Turnseck, accepting what she told him at face value.
Whether the full details would ever have emerged had the witness not come forward can never be known.
No effort was made by anyone to conceal the damaged car, which remained in Mr Buswell's driveway yesterday, more than two weeks after he crashed it.
Allegations of a political cover-up - beyond Ms Turnseck's decision to deal with the car crash at some later date - do not fit the facts as The West Australian understands them.
The Premier insisted his failure to ask questions was not because he did not want too many answers, saying he would not have changed anything about how he handled the situation.
The Police Commissioner undertook to release the witness' phone call to police in the interests of transparency, but not until the investigation by police - who yesterday took a statement from the witness and finally attended Mr Buswell's home - was complete.
That, he said, was a relatively simple matter that could be wrapped up within days.
How long that takes will depend in part on whether Mr Buswell is well enough to tell police what he can recall.
"I think everyone has the responsibility to co-operate," Mr O'Callaghan said of Mr Buswell's responsibilities to the investigation.
Mr Barnett remains hopeful Mr Buswell can return to Parliament as the member for Vasse.
"My concern now is obviously for Troy's welfare," he said.
"I think it's a very sad day and it's a sad situation that he finds himself in.
"And again, while I understand the significance of today's events, I again would ask you to respect his privacy and respect the fact that he is under medical care."