The recruits were each instructed to do 30 push-ups as part of an assault course on Wednesday night’s episode, however, the former Bra Boy was caught out doing only 15.
The test came right after the contestants had to organise themselves in order of strength, with Koby asking to be put first.
Unaware that he was secretly being filmed, the 42-year-old continuously denied any wrongdoing in the challenge when he was confronted by Chief Instructor Ant Middleton.
He later changed his story during an interrogation with the directing staff when presented with video footage showing himself cutting corners.
“I didn’t mean it, no way. I just wouldn’t have cheated that much,” he began. “But the evidence is there and I’ll take full responsibility.”
Koby was then instructed to inform his fellow recruits that he had cheated and they would all be punished for his actions.
“I was supposed to do 30 push-ups and I did 15, I don’t know how I did it but that’s why we’re getting tortured tonight,” he told the others upon his return.
The ex-professional surfer continued: “They’re basing my whole integrity on 15 push-ups in front of a camera and I promise you I can do as many push-ups as all of you together.
“I just f**ked up, I counted wrong and I didn’t keep counting. I didn't mean to do that, but I promise that I did that time trial faster than any one of you.”
Viewers immediately took to social media to share their thoughts on the incident, with many saying that he should withdraw himself from the competition.
“Surely Koby could’ve just apologised to the team properly instead of dragging on and feeding his ego,” one person tweeted.
“Koby is a little confused by the meaning of integrity, he seems to think it means being better than everyone else,” someone else wrote.
“So cringe hearing old mate talk himself up!” another added
“Koby might be a bra boy, but against Ant, I think he’ll be out of his depth,” a fourth shared.
“I can only think that Koby was counting the up and down of his push-ups instead of just the downs and that’s how he got to 30 so quickly,” a user suggested.
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