He only needed one more winner - the odds-on favourite Envoi Allen - for the full lot, but decided to take £250,000 if his final horse didn't win, and £300,000 if it did.
With his other bets, that could have amounted to as much as £322,000 after the race was done.
It's a good job he did cash out, too.
The hot favourite in the 1:20pm Marsh Novices' Chase fell, meaning that he'd have won absolutely nothing if he had let the bet ride.
Take a £275,000 cash out offer? Or let an extraordinary £500k acca ride?
That's the dilemma facing @istabraq_king with Envoi Allen 4/9 to win Thursday's first race at Cheltenham.
What would you do?#CheltenhamWithBetfair
- Betfair (@Betfair) March 17, 2021
But, that's not what happened. He did cash out, and now he's sitting on a cool quarter of a million.
Speaking to The Daily Mirror, Paul said that he'd never planned on letting the race go off, but was confident that Envoi Allen would win, having put in the hours of research.
As anyone who bets on horses knows, hours of research are worth nothing if the horse falls over.
That's what makes his decision even more special.
Paul celebrated his big windfall last night with a bottle of champagne and agonised over what his final decision would be, alongside his parents.
Celebrating the Bob Olinger victory while deciding what to do pic.twitter.com/y7E3OouOc8
- Paul Dean (@istabraq_king) March 17, 2021
In the end, he said: "I am over the moon and I am just so happy I had the money secured but could still enjoy the last race properly thanks to Betfair letting me cash out.
"It wasn't quite ambition achieved but I'm really happy with the result, of course.
"My parents were insistent I take it but I had to have a think. I don't think I was every really going to risk the £500,000, but I still wanted to enjoy the thrill of the last race with Envoi. It took a lot of thinking but Betfair were great and offered me the partial cash-out."
He continued: "Everyone thinks I am joking but I am actually quite calm watching the races come in, I know they are going to win, my mates called me Iceman.
"My real worry is three months beforehand hoping they don't get injured and miss the festival.
"I have been betting since I was five, I study the form in great detail, sometimes eight hours a day.
"This win means I can finally spend more time betting seriously which is what I love to do.
"I have always wanted to do it more but only took the leap 18 months ago and it looks like it has finally paid off. It feels like I am living my dream."
Now, he's off to New York - his favourite place - then off to Las Vegas with his family. He also plans to invest in a horse for himself and buy a house of his own.
Not bad for a fiver.
Also, he's definitely going to be coming back for another crack at the festival.
He added: "I don't see why I can't do it again, I will back next year for sure as long as they allow me to keep betting, it's what I love to do."
Featured Image Credit: Reach/Teesside Live
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