A court heard that officers knew that 33-year-old father-of-three army Private Vincent Limbani was going to get a taxi to return to his vehicle and drive home and stopped him when he got behind the wheel again.
Limbani's lawyer, Pauline Chapman, told Inverness Sheriff Court it was a "disturbing" case and Sheriff Margaret Neilson also expressed surprise that police had returned his car keys.
The court heard that Limbani had been wakened at around 3am on April 19 this year by his stepson having an asthma attack at` their home in military accommodation in the city.
Mrs Chapman said he had been drinking earlier in the evening and took his car to find an all-night chemist.
Sheriff Neilson told Mrs Chapman: "There are mandatory disposals unless there is a special reason not to disqualify. Do you want a proof fixed for a special reasons hearing?"
Mrs Chapman confirmed she did and added: "I am advised that if he is sentenced to more than 100 hours of unpaid work, he will be sacked from the Army." The proof was set for September 8.