His drinking companions pushed two tables together and laid him out until medics arrived to whisk him to hospital with a suspected heart attack. The usually raucous atmosphere was a little subdued after that, but an hour later he was back - he'd discharged himself because he'd left a half-finished beer behind.
Na Dvorku is tucked into a courtyard a block from the main square of Ceske Budejovice, a provincial capital about three hours south of Prague by train. The city's main claim to fame is Budvar beer, also known by its German name of Budweiser (no relation to the so-called beer of the same name brewed in the US).
Like all traditional Czech pubs, at Na Dvorku the beer comes to you. There's no queuing at the bar and any time your glass drops below quarter-full, the waiter slams a fresh beer on your table and marks your tab. You only need to signal the waiter when you want him to stop bringing beer.
Na Dvorku isn't flash - its punters tend to be overall-clad workers, students and the odd stray tourist - but that doesn't mean its staff don't take the business of beer seriously.
Head barman Antonii Husak told me, over the clinking of glassware and shouts of "Ty vole!" (You ox!), that the key to a perfect pint is serving it at the right temperature, 4-6C, and coaxing it from the keg in stages to guarantee a lasting head.
"The head must be thick like cream and should hold for several minutes. You have to tap three times, wait each time until the foam falls, and then top it up again until the glass is filled to the mark and a foam cap rises above the rim. The head acts as insulation, stops gas escaping and preserves the taste longer," Husak said.
And if the glass has the slightest trace of grease or the pipes aren't clean, the head collapses instantly and won't leave rings around the glass as it's drained.
"Then customers get angry and they're gone ... Czech drinkers are very demanding," he sighed.
And what of the beer itself? To find out what makes Budvar special, I caught a trolley-bus across town to meet brewmaster Josef Tolar.
You get an idea of this brewery's place in the Czech psyche when you learn it was one of the few businesses the state held on to in the post-revolution privatisation frenzy of the 1990s.
Many a patriotic Czech spent the decade lying awake at night fretting that the Americans would buy the brewery and promptly shut it down, opening the European market up to the US Budweiser.
Tolar is not exactly charismatic - grey moustache, grey suit and a passion for the minutiae of brewing chemistry - but groups like Britain's Campaign for Real Ale see him as a guardian of brewing traditions, one of the few holding out against the cheap 'n' fast methods of the multinationals.
What distinguishes Budvar from other beers, Tolar said, is water from a 300m-deep on-site well, Moravian malt and Saaz hops grown in a handful of Czech villages. And although most breweries use hop granules or a Vegemite-like extract to add bitterness to their beer, Budvar uses dried hop cones straight from the vine.
But perhaps the most crucial difference is the lagering or storage period. Nowadays most large-scale breweries age their beer for a month in a conical tank, whereas Budvar keeps its beer in the old-style horizontal tanks for three times as long.
"We say 35 days is sufficient for a draft beer, but for lager you need 90 to 95 days. It is not economic, but it is the traditional way and gives the best results," Tolar said.
But the punters at Na Dvorku know the one really important thing about Budvar. It tastes very, very good.
Na zdravi! (To health!)
CHECKLIST
Getting there: Air New Zealand flies to London, from where a range of budget airlines connect to Prague.
