The alleged nautical mishap took place only a week before the driving incident, which his lawyer Steve Cullen described as "pretty extraordinary".
In the early hours of April 13, police spotted Harmer driving erratically on Otaika Rd in Whangarei.
They found the doctor - who has nine years medical experience - drunk with a dislocated shoulder.
An initial breath test indicated he was over the limit and a blood sample was taken in the ambulance as he was driven to hospital.
It gave a reading of 110 milligrams of alcohol per 100 millilitres of blood - more than twice the new limit.
Ordinarily the charge carries a mandatory six-month disqualification and a fine but the explanation for the events persuaded Judge Dawson no punishment was warranted.
Mr Cullen said his client had been invited to the party with a friend and had planned to stay there the night.
After drinking punch through the evening, some other revellers "took umbrage at the 'jafas' being at the party" and set upon Harmer.
As a former orthopaedic registrar, the court heard, the defendant would have been aware of the possibility of permanent nerve damage if his injured shoulder was not treated.
"You were in a position where you had no choice [but the drive]," Judge Dawson said.
The judge was also swayed by submissions that Harmer's burgeoning medical career would be stalled with a conviction to his name.
Mr Cullen said his career progression would likely see him required to travel abroad for a fellowship and it "might be difficult" with the black mark on his record.
Harmer refused to comment on either case outside Auckland District Court today.
He will be back before the court next month.
