Mr Allan, a drug dealer, was sprayed in the face with degreaser and then bashed at his home at 47 Goodenia Street, Rivett, on December 17, 2017, according to an agreed statement of facts tendered in court on Thursday.

While Mr Allan crawled down the street leaving a trail of blood as he desperately sought help, Colin Maxwell Booth, who on Thursday admitted involvement in the killing, first robbed the home of drugs, a phone and a credit card and then left the scene in a taxi to get McDonald's, in clothes that surveillance footage from the fast food restaurant showed were stained red.

Booth, 35, was arraigned in the ACT Supreme Court on Thursday and convicted of the charge of manslaughter by Justice David Mossop. He admits liability through an agreement with his co-accused to assault Mr Allan, but does not concede he delivered any blows.

According to the agreed statement of facts, Booth joined his co-accused at the Rivett home for the purpose of getting drugs, and contends he stayed outside while the other two went inside.

His two co-accused have pleaded not guilty to murder and are due to face trial next month. They have not been named for legal reasons.

Prosecutors say after the incident Mr Allan crawled down the street until he reached a home about six houses down, where a medical student lived, about 5.30am.

Once there he knocked loudly, and the occupants could hear him breathing heavily and yelling out "Please". Scared, the people inside ran to the back of the house and called police.

When police arrived the medical student opened the door to an unresponsive Mr Allan and began CPR until paramedics arrived and took over.

A forensic pathologist said Mr Allan died of cardiac arrest.

"There were several contributing factors to the cardiac arrest, including pre-existing heart disease and the very high level of methamphetamine in the deceased's blood at the time of death," the statement of facts said.

Booth "accepts that the blunt force injuries sustained in the altercation and the exertion, stress, anxiety and adrenaline associated with that event were also contributing factors".

Mr Allan fled from his alleged attackers, crashing into Booth and knocking him over before continuing down the street. Booth denied knowing how badly injured Mr Allan was, but admits he entered the house and stole drugs, a credit card and Mr Allan's phone.

He and a co-accused called a taxi and stopped at the McDonald's in Manuka, where surveillance footage shows red staining on Booth's clothing.

About 10am that same day, Booth and a co-accused went to Coles Liquorland in Manuka and used Mr Allan's credit card to buy a 1 litre bottle of Bundaberg UP Rum and a 1 litre bottle of Bailey's Irish Cream, as well as a 10 pack of Wild Turkey and Cola.

In the days afterwards, Booth used Mr Allan's phone.

He will be sentenced at a later date.