At about 5 o'clock in the afternoon, on the floor of parliament, the Opposition seized its opportunity.
It noticed many Coalition MPs had left the House, including senior ministers such as Peter Dutton, Michael Keenan and Christian Porter.
With numbers in its favour, the Opposition defeated a motion to adjourn the session, 69 votes to 67.
Then chaos ensued.
Absent Government MPs were told to hurry back to the House, including a surprised Treasurer Scott Morrison, who was speaking to Sky News at the time.
"... higher taxes, because they know that will frustrate the economy and ... uh ... do ... I'm sorry, Paul, we're going to stop, people are banging on the door ... "
Reporter: "Sure."
"What? ... There's a division, mate, I've got to go."
Reporter: "Okay, see you."
Three votes were passed in favour of the Opposition, and Labour came within one vote of successfully passing a final motion for a royal commission into banks.
A day later, Mr Morrison has dismissed Labor's move as a "stunt."
But Labor frontbencher Tony Burke says the Coalition was being arrogant.
"They wanted to characterise this as some sort of stunt. The outcome that we were seeking is exactly what we've been saying we would seek for months now. It's not like we've been a little bit subtle that we'd be pursuing something like this. But the Government has been sufficiently arrogant, sufficiently disorganised, sufficiently incompetent that, for the first time in more than 50 years, the opposition took control of the floor of parliament."
The leader of the House, Christopher Pyne, has acknowledged it was a mistake in an interview with the Nine Network.
"There's no doubt that what happened late yesterday afternoon was a stuff-up, and, those people who weren't there, obviously, they learnt a valuable lesson -- in fact, everyone learnt a valuable lesson -- but there's no point in pointing the finger at individuals. Truth is that, in the 43rd parliament, the Gillard Government, Anthony Albanese lost 61 votes on the floor of the House of Representatives. These were three procedural votes, and, quite frankly, people out there in the community are more worried about jobs, they're more worried about feeding themselves and their children, than they are about three adjournment votes in the House of Representatives."
Mr Pyne says he did not give MPs permission to leave the floor.
Justice Minister Michael Keenan was on a plane to Melbourne when he received a message to come back.
He has accepted responsibility for the mistake in an interview with the ABC.
"Well, I take full responsibility for that. It was my decision, and, obviously, all members of parliament should always be available for votes in the House of Representatives. I've been in the House for 12 years, and I've never missed a division, and I won't be missing any in future, and, obviously, this has been a salutory lesson. Look, we had some late-breaking mail about a significant operation within the AFP. I wanted to do something in relation to that, but, look ... it was a work-related matter, but the rationale doesn't matter. I mean, every member needs to be available when the parliament is sitting. And, obviously, I failed in that."
It is an embarrassing setback for the veteran MPs and Prime Minister Malcolm Turnbull, who could have faced a motion of no-confidence.
Although, Labor's victories were on procedural votes rather than legislation, they have undermined the Coalition's claim of having a stable, majority government.
Labor frontbencher Anthony Albanese has told Sky that MPs should know the difficulties of managing tight numbers in the House of Representatives.
He was referring to the years of a hung parliament under the Gillard Government.
"We were in control, as you know, Tom, of a minority government for three years, and we were in control each and every day on the floor of the House. This mob couldn't last three days, even though they say they have a working majority. What's very clear after last night for all to see is that they don't."
The Coalition finally regained control two hours later, winning 73 votes to 72 to adjourn the House at 7:22 in the evening.
Mr Turnbull says it is a lesson the MPs will not forget.
"Two of them were Cabinet ministers, and one of them was a minister. They're grown-ups, they're experienced parliamentarians. They knew that they should not have left, and they left early because they thought they'd get away with it. They've been caught out, they've been embarrassed, they've been humiliated, they've been excoriated, and it won't happen again."
