In May this year, a veteran tour leader noticed that one of his tour members was stricken with altitude sickness while on an overnight train ride to Lhasa in Tibet.
Mr John Tan, a tour manager from Chan Brothers Travel, promptly measured Mr Richard Nai's blood oxygen level before giving him oxygen from oxygen tubes in the cabin.
In June, Mr Nai wrote in to The Straits Times Forum page to commend Mr Tan, 50, for his care and prompt intervention.
The 53-year-old was suffering from acute mountain sickness at an altitude of 3,500m while travelling on the train.
His blood oxygen had dropped to a dangerous level below 50 per cent, from the usual level of 90 per cent and above.
I knew I needed help but I couldn't move throughout the night... My wife was distraught, but John managed to calm her down.
MR RICHARD NAI, commending tour manager John Tan for his care and prompt intervention which helped him recover
Stuck in a whirl of hallucinations, Mr Nai flitted in and out of consciousness, unable to call out for help to his unsuspecting wife, who was sleeping above him on the second tier of a triple-decker bed.
In worst-case scenarios, mountain sickness could lead to a coma, and even be potentially fatal.
Luckily for Mr Nai, Mr Tan realised that something was wrong while doing his daily morning checks on tour members.
Mr Tan, who has had 15 years of experience as a tour leader, said: "When I saw Richard, I immediately measured his blood oxygen level and promptly gave him oxygen from the oxygen tubes in the cabin.
"High altitude sickness is common for Singaporeans coming to Tibet as they are not used to the reduced oxygen levels, but Richard's case was a more serious one."
Mr Nai said: "I knew I needed help but I couldn't move throughout the night. It was only when I woke up to John calling my name that I realised there was an oxygen tube connected to my nose.
"My wife was distraught, but John managed to calm her down. I am really thankful to him for having helped me through a crisis."
Mr Tan continued to tend to Mr Nai while he recovered from his condition. In addition to carrying his luggage and buying porridge for him, the tour manager also looked up return flights for him.
However, after a doctor assessed and treated Mr Nai, he was able to carry on for the remaining seven days of the tour.
Mr Nai, a mechanical engineer who has been on 10 different tours, described Mr Tan as the best tour manager he has had.
He said: "John has the special human touch, and I wrote in about his actions because I wanted to let the public know about a great person in the tourism industry."
Mr Nai is one of many who have commended Mr Tan.
Ms Rebecca Chia, a marketing communications executive at Chan Brothers, told The Straits Times that Mr Tan has received "numerous compliments" for his patience and knowledge from customers who had gone on other tours he led in China.
For Mr Tan, who hopes to continue his job for at least the next decade, the plaudits are welcome acknowledgements of his efforts.
He said that leading a tour is not easy. "But when feedback like Richard's comes in, it gives me a lot of motivation and makes me enjoy the job more," he added.