Taking time to talk to as many staff as possible, Mr Ryall congratulated them for an "absolutely fantastic" day last Thursday, when they treated 100% of patients within six hours.
One of the country's poorest performers, Dunedin's ED has consistently failed to meet the target of 95%, so the one-off result was a morale boost.
Mr Ryall jokingly asked ED improvement clinical champion Mike Hunter: "Is it true there were only six patients that day"?
The department dealt with 107 patients on the 100% day; the week's results included 82% on May 29 (96 patients); 95% on May 30 (105 patients); 96.9% on May 25 (107 patients).
Despite the promising result, Mr Hunter warned the minister the department's problems were a long way from being fixed.
Expected to provide some relief is a $2.7 million ED observation unit opening in late August.
Building work is well under way, and Mr Ryall was impressed with the 10-bed unit's size, which was bigger than he expected.
By caring for patients too sick to go home, but not ill enough to be admitted, the DHB hoped the unit improved its daily ED target performance by 5%.
Mr Ryall's main reason for visiting the hospital was for a presentation on the DHB's rollout of electronic prescribing.
A long-running Dunedin pilot is being rolled out in all DHBs over the next couple of years.
"The Dunedin pilot saw a reduction in medicines errors of over 98% and in some areas such as legibility all errors have been completely removed.
"Imagine what this will mean when it is rolled out across New Zealand," he said in a press release.
During his Dunedin visit, Mr Ryall also announced an extra $4 million over four years to encourage more organ donations.
