For the past two months, his training routine has been at the mercy of the erratic schedule that comes with being an emergency department medical officer (MO).
But neither that, nor having to run into a strong headwind for close to 5km, could stop Mok Ying Ren from finishing seventh at Sunday's Gold Coast Marathon.
His time of 2hr 26min 30sec allowed him to qualify for December's South-east Asia Games in Myanmar. In fact, it was over a minute faster than Indonesian runner Yahuza's gold-medal effort of 2:27.45 from the 2011 Palembang and Jakarta Games.
It was the perfect way for the 2007 SEA Games triathlon gold medallist to celebrate turning 25 on Saturday.
But Mok is not about to get carried away.
"I'm not reading too much into it," he said. "The weather conditions here in the Gold Coast were much better than in Indonesia two years ago."
He explained that yesterday's race temperature of between 12 deg C and 14 deg C fit perfectly with his penchant for running in cold conditions.
However, the temperature in Myanmar in December is unlikely to see anything below 16 deg C.
That said, Mok is optimistic that he can still improve in time for the biennial Games.
After all, there is around just one month left on his attachment to Tan Tock Seng Hospital's emergency department.
Once that - and the erratic working hours - ends and he begins a fresh stint at a polyclinic, he will be able to resume his strict training regimen that sees him clock more than 100km a week.
"It has been hard to get into a routine," he told The Straits Times. "But once I start training more regularly, I expect to get better."
Still, there is one uncertainty left: his imminent return to serve the final 18 months of his deferred national service could impact his quest on SEA Games gold.
Mok is scheduled to resume his service as an MO on Dec 2 - a little over a week before the Games get under way in Naypyidaw on Dec 11.
"That's the challenge," he stressed. "In terms of fitness, I'll be much better; but in terms of race-day performance, we'll have to see."
Even so, the Republic's top marathoner remains confident.
"I'm definitely going for a medal. Honestly, I don't think it will be a problem at all," said Mok, who has made no secret of his dream to race at the 2016 Olympic Games in Rio.