Afghanistan Peace CampaignThree Spanish travellers and three Afghans were killed and five others, including McDowell, were severely injured.
Islamic State has reportedly claimed responsibility.
McDowell said he was chatting with his travelling companions in a van in a shopping district when the gunman opened fire.T
“It was rapid, like ‘bang, bang, bang, bang’ … like firecrackers,” he told Australian Associated Press on Thursday.
McDowell, an engineer from Perth, said the gunman – who was armed with an AK-47 Kalashnikov rifle – fired into a shop that some of the group was in before turning on the van.
“Bullets started coming through the windscreen … We were fish in a barrel,” he said.
“I flung the door open and ran … Then I felt a slap on the arse.”
McDowell had been shot in the right buttock from close range as he attempted to escape the hail of bullets but did not realise at the time.
“I spun around and he was looking at me, pointing the gun,” he said.
The avid hockey player dropped to the ground and rolled under a car, fearing for his life.
“He came and stood beside the car … and I thought this is where he’s going to squat down and shoot under the car,” McDowell said.
“That was the moment I thought ‘I might die here’. I wasn’t scared. It all happened too quickly. I had too much adrenaline.”
The gunman continued firing indiscriminately. Three of McDowell’s tour group who were trapped in the van suffered serious gunshot wounds.
Watching the gunman’s feet, McDowell saw him turn and take a few steps away from the car, allowing him time to “wriggle out” and run to safety down an adjoining alleyway.
After the shooting stopped, McDowell walked back to the van and shops, where he found a gruesome scene and the bodies of two of the three dead tourists from his group.
“We’d only known each other for a couple of days, but when you’re in that sort of environment you become mates quickly. It’s just so senseless.”
McDowell and the other survivors were taken to a local hospital for emergency medical treatment before being transferred to a Kabul hospital, where he had surgery to remove bullet fragments from his buttock.
“It hit my arse cheek and burst and left a heap of shrapnel,” he said.
He has since been able to fly out of Afghanistan with his fellow travellers and was expected to return to Australia in the coming days.
McDowell said he had no doubt the gunman, who fled the scene, was targeting tourists.
Multiple foreign tourism companies offer package tours to Afghanistan, often visiting cities such as Herat, Mazar-i-Sharif and Bamiyan.
Bamyan is home to a Unesco world heritage site and the remains of two giant Buddha statues the Taliban blew up during their previous rule of Afghanistan in 2001.