Cox, who has reached the Judges' Houses stage of the competition, said that he opted for an early night when the hopefuls were given drinks and a pool party at Boot Camp.
"I was surprised. I expected people to be a lot more cautious," he told Digital Spy.
"When there are cameras around and booze about, I thought people might hold themselves together and be more sensible. But some people just let loose and really went for it.
"Me and a few others just let them get on with it and have their partying, while we prepared for what was to come."
> 'X Factor' Judges Houses: The Boys - Who should make the Live Shows?
Cox added: "I enjoyed myself. But I wasn't one of the ones going crazy. I went to bed quite early and I had a feeling that something might happen the next day.
"I was really, really cautious about wasting an opportunity and messing up chances. I wanted to have a good time, but I wanted to stay focussed."
Gary Barlow will reveal on Sunday's Judges' Houses show whether Cox has made his Top 4 Boys and the X Factor Live Shows.
Click along Digital Spy's gallery below for pictures of all 32 remaining acts, who will be fighting it out at Judges' Houses.