He also left some time after the 23 other athletes in the race had finished, but did so with a new national record to his name and the cheers of a packed crowd still ringing in his ears.
His homeland in Oceania is more than 9,000 miles away, but on Sunday he was an honorary Scot.
Lapped three times, the 17-year-old was roared on down the home straight and, arms and legs still manfully pumping, he crossed the line in 16 minutes 55.33 seconds.
He was more than one-and-a-half minutes behind the second-last finisher and more than three-and-a-half adrift of winner Caleb Mwangangi Ndiku with his dyed gold hair.
The Kenyan had won the title, but Siosi had won the crowd.
Siosi thanked the Scottish public for getting behind him and spurring him on when he felt like quitting.
"I feel so tired," he said. "It was too cold for me. It was difficult to finish the race. I almost gave up, but the crowd were shouting, 'Go! Go!', so I had to finish the race.
"I'm privileged to compete against the fastest people in the world.
"The boys who train in Kenya train at altitude, whereas I just train at home - no coaches, just on my own. I was lucky to compete. They encouraged me really well."
The teenager will use the experience gained in Glasgow as motivation to step up his training ahead of the Pacific Games in Papua New Guinea next year and the 2018 Commonwealth Games on Australia's Gold Coast.
"I will go back and train harder for the next Commonwealth Games," Siosi added. "This is my starting point for the Pacific Games. I will go for gold in the Pacific Games."