Then 16 years old, the pole vaulter was still recovering from a tear in his left quadricep muscle when he made the trip to Laos. And although he did not have any medal expectations, he was still excited about taking part in the biennial regional meet for the first time and confident of clearing the bar at competition.
"That was so disappointing," recalled Lim, then a Secondary 4 student at Hwa Chong Institution. "Since then, I have been waiting for the opportunity to erase those bitter memories."
The 20-year-old national serviceman will finally get to do so this December. Thanks to his national record-breaking feat at the Singapore U-23 Open Track and Field Championships last Sunday, Lim has been given the green light by the Singapore National Olympic Council (SNOC) to compete in the SEA Games in Myanmar.
He had cleared 4.83m to break the national mark of 4.82m set by his training mate Chan Sheng Yao at last April's National Schools Track and Field Championships.
The two heights mean that both Lim and 18-year-old Chan had met the SEA Games qualifying mark of 4.70m, which was the bronze-medal winning height set by Singapore's Edwin Chong at the 2011 SEA Games.
Chan and Chong had initially been selected for the Myanmar Games. However, Chong has withdrawn because of overseas studies.
As such, the Singapore Athletic Association (SAA) had hoped to replace Chong with Lim even though the nomination window was closed — and were delighted when the SNOC agreed to their request yesterday.
Said Loh Chan Pew, SAA's Chief of Sports Development and Performance: "We're very grateful to the SNOC and we now hope that Sean can do us proud in Myanmar."
Lim also hopes to do so even though he only resumed training once a week four months ago. "I've not been able to train the past two years because of NS," said the army signaller who missed out on the 2011 Games because of his A-Level examinations.
"And I will have just a week of full training for the SEA Games when my NS ends in December. But I take my new national record as a good start in my return to the sport, and I hope to do well at the Games."
Pole vault coach David Yeo, who trains both Lim and Chan, is delighted that both will be in Myanmar.
"Sheng Yao was Sean's junior at Hwa Chong. So Sean will be able to guide him there and both will be able to push each other," he said.
In all, the SAA will have 25 athletes at the Games after thrower Scott Wong, who is studying in Britain, and distance runner Anne Qi Hui pulled out because of school and work commitments respectively.