It strikes me as entirely possible that the natural SARS-COV-2 virus had been collected in samples from patients with weird symptoms and was being studied in the local main lab with good containment facilities.
This is late 2019, no particular urgency, because not many people are ill and contact tracing is showing only low transmission. People think it's a SARS variant and aren't worried because SARS has been contained before. They'd be right only about the first bit.
But then, the virus, still of course out there in the world from which it was captured, shows how it boosts its transmission by having seemingly random superspreading events. There's one in the wet market, perhaps others, once past the 'smouldering in the background' level of transmission it flips into major problem in just a few weeks.
But at least there's a sample in a lab and it's already been sequenced. That can rapidly be released to international reasearchers, and official permission won't take as long as it used to because international co-operation has improved, and also the case numbers are rising and the containment measures are ever more conspicuous.
The SARS variant is indeed that (hence the eventual name) but the effect of the changes has made it a whole novel strain.
TL:DR it didn't need to escape from the lab if it was captured from the wild, as it will still exist in the wild