The former banker-turned whistleblower then handed the receipt to his employer, Copenhagen-based Danske Bank, which has since has become embroiled in one of the world's biggest money laundering scandals.
The 2012 episode, described by Wilkinson's U.S. lawyer and confirmed by the Estonian hospital, sheds light on the nature of the previously obscure 47-year-old, who helped lift the lid on 200 billion euros (177.32 billion pounds) of suspicious payments flowing from countries such as Russia through Danske to the West.
Wilkinson, the former Baltics head of trading in Danske's markets division, says he stumbled across the scheme in 2012, reported his concerns to bosses in 2013 and 2014 and assumed they would fix it.
He was wrong.
He told shocked European and Danish lawmakers last week that at least 10 banks, including large U.S. and European lenders, funnelled money through Danske in Estonia, Lithuania and Denmark to the U.S. and out into the financial system between 2007 and 2015.
Billed by some as a hero in a global fight against dirty money, Wilkinson said he felt he had "done something good for society" - but never wanted a lead role in the Danske drama.
A former colleague says he has a "black-or-white" view of the world, which could at times lead to conflict at work. But he was not regarded by workmates as driven by greed.
"He liked his job," he told Reuters.
But after filing four whistleblowing reports about large flows of suspicious-looking transfers and seeing little action from Danske, Wilkinson quietly resigned in 2014.
Denmark's largest bank eventually published a report in September that detailed its own compliance and control failings and now faces investigations in Denmark, Estonia, Britain and the United States.
INTO THE SPOTLIGHT
Wilkinson was dragged into the public spotlight after an Estonian newspaper published his name in September and, while outraged at the "gross abuse of human rights", has used his podium to demand protection of informants to allow a crackdown on crime.
Wilkinson urged lawmakers last week to ban non disclosure agreements (NDAs) that prevent whistleblowers reporting wrongdoing to authorities, to investigate the Danish FSA regulator for potential misconduct and to police secretive shell companies that hide their owners identities.
Picking his words carefully to avoid the pitfalls of his own NDA and Danish bank secrecy laws - so stringent they surprised some Danish lawmakers - he told European Parliamentarians that employers could retaliate against whistleblowers if they stepped forward.
Flanked by Stephen Kohn, a leading American advocate who secured a $104 million (81.50 million pounds) financial reward for a UBS whistleblower in 2012 under a U.S. bounty programme for informers, Wilkinson said other informants were too afraid to speak up for fear of losing their jobs and livelihoods.
"I strongly believe there were a number of more junior people in the (Estonian) branch who ... knew that there were suspicious things, but because of the set up ... would never come forward as a whistleblower," he said.
SEASON OF GOODWILL?
A sometimes nervous-looking Wilkinson, wearing a suit and tie with his top shirt button undone, rose to the occasion when he took to the global stage, even cracking a joke about reporters calling his mother-in-law in a small town in Estonia.
"How am I going to get a Christmas present this year?" Wilkinson, who lived with his family outside Tallinn, told about 100 people at the European Parliament hearing in Brussels.
Against the backdrop of criminal investigations, plunging shares and a boardroom rout at Danske, Wilkinson said he remained at a loss to explain how controls failed at Danske and at other banks, that sources have named as Deutsche Bank, JPMorgan and Bank of America.
Deutsche has confirmed it acted as a correspondent bank for Danske in Estonia but ended the relationship in 2015 after identifying suspicious activity. JPMorgan ended a correspondent relationship with Danske in 2013, according to a person familiar with the matter. Bank of America has declined to comment.
Whistleblowers who participate in wrongdoing can still claim financial rewards from U.S. authorities, because they are seen as essential to uncovering hidden white-collar crimes. But Kohn says Wilkinson, with his balding salt and pepper hair cropped short and sporting spectacles, is not one of 42 people reported to authorities over the scandal - eight to the police.
In the meantime, Wilkinson has spoken of his frustration at the curiosity about him, rather than about where the cash flows ended up.
"I don't want to be in the public profile, I never volunteered for it ... And what I would really like right now is to go back to my wife and kids," he said.
When he left Danske in 2014, he said a senior executive flew over from Copenhagen with an NDA that awarded him six months salary under a non-compete agreement - and an extra 20,000 euros. The executive looked him in the eye, he said, promised he had zero tolerance for money laundering and would "fix it".
"I've got a family, I'd got what I wanted which is someone telling to my face, looking me in the eye, that he was going to fix it... I took the view that the right thing to do what to take his word for it and take the money."
(Writing by Alexander Smith; Editing by Keith Weir)
By Jacob Gronholt-Pedersen and Kirstin Ridley