Barnes and his family were on their way to dinner in Bangkok when he decided it'd be too hard to negotiate the pram along the bumpy, busy road that runs beside the Thai capital's popular Erawan Shrine.
Instead he led his family to an overhead walkway.
As they jostled for space with other pedestrians, high above the road way, a bomb exploded outside the shrine with terrifying force, killing at least 21 people and injuring 123 others.
So far there've been no reports of Australians injured or killed, but the Department of Foreign Affairs is consulting with Thai officials.
Barnes is still wrestling with the shock of what might have happened to his Thai-Australian wife Jane, daughter Elly-May, son-in-law Liam Conboy and grandson Dylan if he hadn't decided to change course.
"I had the pram with the grandson ... walking past the shrine would have been very difficult because it's a bumpy road. So I said to the kids 'follow me, I'll take you this other way'," he told AAP from his Bangkok hotel.
"We were literally walking between two buildings on the walkway when the bomb went off. It was just frightening.
"I knew it was a bomb straight away. All the windows sort of went whoosh and bent from the blast."
