He and Olive woke the man and propped him up.
Yates: "He was spewing up everywhere.
"He had some liquor and hooch in his pocket and his eyes were going back in his head — he was definitely on something else."
Olive, who's had first-aid training, says they cleared his airways and kept him awake while an ambulance was called.
Yates says they established the man was a Kiwi from out of town staying at the nearby Juzy Snooze.
He estimated he was about 25.
While the pair kept him conscious, fellow darts player Steve Hanrahan kept an eye out for the ambulance.
"Me and Jonny felt pretty chuffed," Olive says.
"We were doing our bit, as the Prime Minister says, 'be kind to each other'."
All three were annoyed about the man who left the victim for dead.
Olive: "You check someone's OK, don't you?"
Yates: "It's not the mentality of Queenstown. I don't want to cast aspersions out there, but if he'd have been left, he could have drowned ..."
St John spokesman Gerard Campbell confirmed the ambulance was called at 2.47am and dropped off the man at Lakes District Hospital at 3.20am.