A University of Canterbury society knew a student was going to jump off a roof as a stunt, but says it was only told "half the story".

The 20 year old was seriously injured after he lit his hair on fire and jumped off the roof of his two-storey Christchurch flat into an inflatable pool on September 16.

The stunt was part of his candidacy for the committee of the University of Canterbury Engineering Society (Ensoc). It was filmed and was to be played at the Ensoc AGM. He remains in hospital with a fractured spine.

An ebola satire was among the controversial entries in the 2014 RoUndie 500.

Ensoc's incoming president Campbell Dawson said on Monday the student had notified the society he was planning on jumping off his roof into a pool.

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"We got told half the story. We were told he was jumping off a roof into a pool and to me that sounds fine.

ANDREW MACKAY/ SUPPLIED The aftermath of riots in Dunedin after the Undie 500 in 2009.

"I've jumped off a fence into a pool, my roof into a pool. He did not say paddling pool or anything to that sort of extent."

The society has made several changes since its AGM two weeks ago, including removing the stunt requirement and adding a position for younger students to help carryover information from previous committees.

"There's never been a serious incident before and we've actually brought in this screening process to reduce the risk and obviously it didn't work properly so we've just scrapped it because it's too risky."

Kirk Hargreaves Entrants dressed as Smurfs for 2007 edition of the Undie 500.

Performing a stunt was "tradition", Dawson said. His stunt was being shot by a paintball gun while doing maths, while other students had eaten vomit.

The injured student took it too far, Dawson said.

"It was almost just a communication breakdown and just the fact it wasn't clearly communicated exactly what was being done. If we knew we would have said 'no, do something else'. We would have given a suggestion to do something a bit less risky."

GEORGE HEARD/FAIRFAX NZ The 20-year-old engineering student lit his hair on fire and jumped off the roof of his two-storey Christchurch flat into an inflatable pool on September 16.

The incident is not the first time the society has come under scrutiny.

The infamous Undie 500 pub crawl from Christchurch to Dunedin came to a halt in 2009, after the rally deteriorated into a weekend of violence in Dunedin. It led to 67 arrests and police in riot gear had to storm mobs of students burning furniture.

At the reworked event in 2014, some students dressed costumes poking fun at women, Islam, Malaysia Airlines victims and the deadly ebola crisis.

Dawson said the society did not have an issue with its culture.

"I don't believe that Ensoc creates any culture, I believe it's the students doing it. We try and provide a party or a event that is safe and we put in all the guidelines we can to try and make it as safe and fun as possible but then there's always some individuals that just take it too far."

DB Breweries and insurance company MAS pulled their sponsorship of Ensoc after the latest incident. Dawson said losing DB Breweries was "probably good in a way", as the society looked at having more "positive events" and less alcohol.

The past two weeks had given the society an opportunity for "very sobering reflection", Dawson said.

"As bad as the incident was, it's now given us an opportunity to change a lot of things about the club and to change the direction that it's heading," he said.

"We've met with the university, the senior academics and they've offered us a lot of support with how we can change the club and help change the perception of the club."