Const. Rueben Paul was just three weeks out of the police academy when he found himself standing in the wreckage of a house, holding a crying seven-year-old boy.
That boy was Kai Dunbar, whose baby brother Nate was trapped under the wheel of a drunk driver's car which had crashed through the family's Merriwa home.
"It was just absolute destruction," Const. Paul recalls.
"I saw a young boy on a bed, standing up. I thought 'He doesn't need to see any more of this'."
He lifted Kai out of his bed and carried him to safety.
Despite the efforts of Const. Paul and fellow officers, Nate was crushed and died.
Const. Paul went outside, where the drunk driver, Melissa Ann Waters, was being held by another officer.
Hysterical, she asked him: "Have I killed the baby? Have I killed the baby?"
"I didn't know what to say to her," the young officer says.
"I remember being handed this paperwork and I said, 'I can try, but I just got out of the academy three weeks ago'."
It was a baptism of fire for the probationary officer.
"You don't know how you are going to react. I don't really know these people but it still affects you.
"I went a bit quiet for a few days, but after that I was OK."
Eleven months later, The West Australian joined Const. Paul on the front line of the fight against drink-driving.
His manner is genial: "Good evening sir, this is a random breath test."
The drivers who blow into the handheld breath test machine have no idea he has witnessed the horrendous results of a crime which clogs our courts and claims dozens of lives every year.
The booze bus is set up on Lake Monger Drive, Wembley.
Just eight minutes later, the first driver blows over 0.05.
An officer parks the man's car on the grass and he is taken into the booze bus for processing.
In WA, police must wait 20 minutes after the driver's last drink to take an admissible reading.
By then, the man's blood alcohol concentration has dropped below the limit and he is allowed to go, but not before police put him through a random drug test.
A middle-aged woman is next into the bus after blowing well over the limit. She's not so lucky - even after the 20-minute wait, she blows 0.097. Her furious husband waits at their car as she is processed.
She has been caught drink-driving before so she is looking down the barrel at a day in court, a significant fine and losing her licence for a long time.
There will be flow-on effects.
The woman is a volunteer who uses her car for charity work, but laws passed last August mean anyone who blows over 0.08 has their licence disqualified on the spot.
More than 9000 people have been caught since the laws were enacted and statistics suggest there is good reason to stop them driving immediately.
Each year, 7500 people — about half of those caught — are found to be repeat drink-drivers, suggesting they continue to drink and drive despite penalties.
After a few hours, the verge resembles a carpark. The officer in charge, Sgt Peter Shellam, says the booze bus not only caught drink-drivers, it also serves as a warning long after it has packed up and left.
“People see lines of cars parked on the verge in the morning and they know that a booze bus has been there the night before,” Sgt Shellam says.
By the time the officers break for dinner, hundreds of cars have passed through but only a handful of drivers have been charged.
In this business, fewer customers could be considered a success.
Const. Paul says no matter what he sees in his police career, he will never forget that night in Merriwa.
“But you try not to think about it because it’s not something you want to dwell on. It’s too painful,” he says.
“People who are blowing over — I have no sympathy for them. It’s not like people don’t know what the laws are.”
He says drivers should ask themselves a very simple question before they get behind the wheel: “Is it really worth it? I mean really, is it worth it?
“You could lose your licence, get an infringement, you might go to court, there might be an accident.
“And it might not be your life you take.”