After the gig, the group walked to a mate's house to continue partying.
A friend told coroner Sue Johnson that De Bruin had been enjoying the night and was in a good, happy mood.
But about 2.30am, a friend heard De Bruin's Kawasaki Ninja ZX–900C1 motorcycle start up.
He jumped up and saw the taillights of the bike going down the street.
The coroner had no evidence about why De Bruin suddenly left.
About the same time, a truck driver was working.
He had left a chicken farm at 3am and was travelling on Robinsons Rd to Feedco Canterbury in a Foden truck, fully loaded with empty chicken crates.
"As he was about to enter the Feedco Canterbury gateway, [the driver] heard a sound akin to an engine dropping down and tyres on the road," the coroner said in findings released today.
"He saw a light in the right-side exterior mirror and heard a bang. He put his hazard lights on, applied the handbrake and jumped out of the truck."
A manager at the chicken farm trained in first aid tried to save him but de Bruin died at the scene.
Toxicology analysis found alcohol in De Bruin's blood at a level of 76 milligrams per 100 millilitres. The legal blood alcohol limit for a driver aged 20 or over is 50mg.
Methylenedioxymethamphetamine, commonly known as MDMA or ecstasy, was identified in the blood, as was cannabis.
Senior Constable John Isitt of the Canterbury serious crash unit concluded alcohol, cannabis and MDMA were factors in the crash.
Inattention may also have played a part, Isitt said, but speed and fatigue were not considered factors.
Johnson said that her colleagues, police and Waka Kotahi New Zealand Transport Agency have "consistently highlighted" the dangers of driving when having consumed alcohol and drugs.
"The clear dangers of using alcohol and driving are well known and well publicised, but I note that this case, Reenen was driving having used three recreational drugs: alcohol, cannabis and MDMA," she said.
The New Zealand Drug Foundation reports that after cannabis, MDMA is the second most used illegal drug in New Zealand.
"Given the prevalence of the use of MDMA, it is appropriate to raise public awareness of the effects of the use of both these drugs and in particular educate drivers about the effects of these drugs," Johnson said.
"I recommend that these findings are brought to the attention of media agencies in the hope of raising further awareness of the dangers of driving when using MDMA and cannabis and alcohol.
"It is my hope that this will go some way towards preventing further harm to the public."
