Typical Western hypocrisy would be at play and China has no motivation whatsoever to subject itself to that.
Also, SARS-1 escaped twice, in Singapore and Beijing: https://en.wikipedia.org/wiki/List_of_accidents_and_incident...
https://www.politico.com/news/magazine/2021/03/08/josh-rogin...
Distance doesn't matter so much in today's world, when cities are connected by planes.
I doubt there is some legal paragraph which would work here, even in International Law.
https://www.axios.com/timeline-the-early-days-of-chinas-coro...
"Shouldn't they be held liable?"
There's a lot of accidents that happened in the West, specifically the US. Some known, some not.
The West just got lucky but would never admit it either.