"When (Cirque du Soleil) first came to me with this idea, I told them they were crazy," the star Canadian sprinter told The Canadian Press, adding he had never been inside the CN Tower before he started training for show.
In his first excursion, a harnessed Surin inched up to the edge under the watchful eyes of Cirque trainers, then slowly and cautiously leaned into the abyss.
"I asked them, 'Are you sure?' and they said, 'Yes,'" he recalled Saturday. "I can't remember the last time I had such a rush of adrenaline."
The sequence was filmed in May and by then, Surin had practised his lap of the tower at least 15 times, he said.
"I'm not scared anymore," he added with a laugh.
In the scene, which kicked off the lavish opening ceremony, Surin hands off the torch to fellow sprinter Donovan Bailey. Bailey's stunt double then base-jumps off the 553-metre structure.
While fans were left to wonder Friday night just who exactly made the jump, organizers confirmed Saturday morning that it was a stunt double, not Bailey, who performed the daring leap.
But even Bailey himself was still playing coy on Saturday, dodging the question when asked by CBC if he really jumped off the tower.
"I seem to be having these boxes on my bucket list, I'm ticking them off as I go," he said wryly during an interview with the network, which broadcast the ceremony on Friday.
Games organizers said one of the challenges of planning the video — which began with members of Canada's gold medal-winning 4x100-metre relay team from the 1996 Atlanta Olympics running the torch around Toronto — was keeping it under wraps.
The head of the Games organizing committee said when people caught glimpses of the crew during the filming, or saw smoke coming from the iconic Toronto landmark on the eve of the ceremony, they had a simple strategy: deny, deny, deny.
"The planning of it was quite complicated because there was some firsts there with respect to using the CN Tower," Saad Rafi said.
A dress rehearsal that included pyrotechnics had some wondering if the tower was on fire, he said. Others spotted the relay team in the streets before the torch relay began.
"I recall one of my family members... saying there's some guy with a torch running around the city, so I had to say that it was for a promotional video," Rafi said.
Asked about reports that people were base-jumping off the tower, Rafi said a Cirque spokesman just replied, "What base-jumpers?"
Staff and participants were told to keep details of the show to themselves in order to maintain the element of surprise, organizers said.
Only three people had seen the video before Friday, they said, and only five knew the ceremony from beginning to end.
Surin, who was also sworn to secrecy, said it was sometimes hard not to let the cat out of the bag.
For months, friends asked if he was taking part in the Games, he said. When he ran into a friend at Toronto's Pearson airport while accompanied by a Cirque official, Surin said he lied and said he was in town for a panel discussion.
On Friday, he simply told friends to tune in to the ceremony without saying why.
Secrecy wasn't the only concern in planning the shoot, however.
Weather also played a big role, organizers said. So was time of day, because they wanted to film at roughly the same hour the video would be shown during the ceremony.
In planning the jump, they also had to take into account the changing wind patterns caused by all the buildings near the tower.
The stunt drew gasps Friday from spectators who filled the Rogers Centre, temporarily renamed the Pan Am Ceremonies Venue.