His mind was abuzz. Thinking of that next event,of how he would swim the 100m freestyle,but,above all,thinking about his experiences here in Sydney at the Paralympics.
So the 32-year-old sat up in bed,picked up a pen and paper,and jotted down a few words he felt he needed to say.
"Ladies and gentleman,"his letter to the Australian public began."I came here with the hope and aspirations,perhaps a little ambitious,of winning a medal. I wanted to do it. But,with the love you have given me,it has made me feel I am a triumph. I will always carry you in my heart.
"If there is a paradise,this is where it is."
It was a heartfelt letter but in reality it is the Australian public who should be grateful. For anyone who had the privilege of watching him swim would want to say thank you to Vallejos for opening their eyes to what the Paralympics are really about.
We quite often get overcome rightly or wrongly by the pursuit of gold. Sometimes even silver and bronze barely rate in comparison.
Vallejos has not won a medal at these Games. He hasn't really even come close. But while he has no jewellery,he has won the hearts of everyone who witnessed his performances in the pool.
It has nothing to do with pity when one watches the S3 swimmer,who was born with just one leg and neither arm fully formed. To watch the courage of Vallejos can only be described as inspirational.
The Australian public got their first taste of him in action on Monday night when he contested the 200m freestyle final.
He took 4min 42.84s to complete the four laps of the pool doing backstroke,with his arms rotating at a furious rate but after watching for almost five minutes,the large crowd stood and cheered when he reached the wall. They did it again when he contested the 50m breaststroke,and again yesterday in the 100m freestyle.
And no doubt the cheers will be boisterous today when he swims in the 50m freestyle.
He's not the slowest swimmer in the pool over the short distances and would give Equatorial Guinea's Eric"the Eel"Moussambani a competitive race but there was something about Vallejos's effort which had a hypnotic effect on everyone.
"I have really enjoyed taking part and sharing it with the people,"he said.
"That I am involved in sport is just a coincidence. What is not a coincidence is my desire to keep living and enjoying life.
"Swimming is my life. It is like a drug. For me it is an important way to enrich myself.
"I have always been given much love from people wherever I have been competing,and what has been shown here touched me deeply."
Vallejos has been swimming for 22 years. He also tried other sports such as shot put,javelin,discus and table tennis,but his sport of choice was swimming.
It has taken him to three Paralympic Games,and although he is yet to win a medal,it has not diminished his enthusiasm or will to win.
"Winning is important,"he said."Those who say they come to the Paralympics and don't care about winning would be lying. I would love to win a medal,and God willing I will one day. But overcoming one's limitation is very important. That is someone's triumph."
Vallejos lives with his parents and a total of eight brothers,sisters,nephews and nieces in Santiago. He works as an accountant and auditor,specialising in tax law.
He is Chile's only swimmer at the Games,and one of just four athletes competing for the nation at these Paralympics.
He said he had received a lot of recognition in his home country as one of the leading Paralympic athletes,and although he was not a regular visitor to the dais,he felt he had achieved many things.
"I think I have achieved something regarding the opinion people have of disabled sport,"he explained.
"Around 10 or 15 years ago,people looked at a disabled person and thought,‘Should I give them money,should I move away,should I smother them with more help than they need?'
"I think I have contributed to change that mentality."
Vallejos will leave Sydney without a medal when the Games finish.
He will,however,leave enriched by his experience,and so,too,will anyone fortunate enough to have watched him swim and realise they have witnessed a triumph not only of sport,but of life.
Thank you,Gabriel.