He pulled the steering wheel hard left, went to press the brake but instead hit the accelerator.
The two vehicles collided - Hidella Arachchige's vehicle was 3.7m across the centre line at the point of impact and continued to travel at speed into a stone wall and overturned.
Hidella Arachchige, who had no prior convictions, suffered a serious injury to his right arm, which was subsequently amputated.
Bruce, an overseas national, suffered a broken wrist.
Judge Farnan found the consequences of a conviction for Hidella Arachchige, who would find it difficult to obtain future work due to the lasting impacts of his injury, were out of proportion and granted the discharge.
He was, however, ordered to pay $1000 emotional harm reparation and disqualified for six months.