Miles Harrison didn't want to seem rude by turning around to look at a man wheezing loudly but seconds later he was saving that person's life.
What he first thought might be the worst smoker's cough he'd ever heard turned out to be a man possibly taking his last gasp due to a blocked airway.
When that man - Whangarei teacher Tony Henderson - tapped him on the shoulder and rasped out the word "Heimlich", Mr Harrison wasted no time performing the jolting manoeuvre that expelled the blockage.
In the first nano-second, though, Mr Harrison thought the man had rasped out 'Heineken'.
The Tomarata dairy farmer knew what to do - years earlier his teenage sister Janine had done the same thing on him when he was 12.
Mr Harrison later phoned his sister and said, "guess what, I had to do the Heimlich manouevre".
After the "surreal" episode, the two strangers had shaken hands and carried on their separate ways. Mr Henderson was still wheezing, but breathing.
A few days later he found out the painful abdomen he'd been left was due to a broken rib caused during the incident.
It was a small price to pay, he said when he contacted the Advocate, hoping to find out the name of the man who saved him, and saying he believed the Heimlich manoeuvre should be more widely taught.
Mr Harrison's sister Janine saw the Advocate article, and the name of the mystery man was revealed.
Northland St John Ambulance chief Tony Devanney said the Heimlich needed to be done properly and could indeed cause problems.
There has a been a move away from promoting the technique in situations other than by trained people, with a hard back blow recommended for the untrained to do in choking incidents, Mr Devanney said.
"Unless you're trained to do it, don't do it."