Suppose for argument the population of Wuhan was volunteered for an inoculation test of a vaccine for a Coronavirus. An unrelated strain of Coronavirus outbreak occurred and has spread through various populations without dire consequences for the most part.
Those that were part of the population which received the vaccine are suffering a much worse outcome when infected with the second Coronavirus in circulation. Their immune response is different due to a prior development of antibodies from the test inoculation. The challenge response of their immune system fortified with existing antibodies, prompted by exposure to the second Coronavirus could be a critical factor.
Those in China are mandated by law to be vaccinated on demand of their government.
https://www.loc.gov/law/foreign-news/article/china-vaccine-law-passed/
Not sure the particular one you wrote about would work out the way you propose.
There is a hospital-associated infection caused by a bacterium called Serratia. It makes a distinctive red pigment on certain types of media.
Believing it to be harmless, in 1950 the US released lots of it off the coast of San Francisco in Operation Sea Spray, which demonstrated the ability to spread an infection over a wide geographic area from a standoff position.
One problem. It wasn't harmless.
Using "it's just a harmless virus" rationale, it is POSSIBLE that some type of airborne pathogen dissemination system was tested, with disastrous results.
The science about a "virus created in the lab" is in, and it strongly points to natural evolution.
But natural evolution really doesn't fit the epidemiology in China.
Your post is very similar to the conclusions I posted back on 2/13:
http://www.freerepublic.com/focus/f-news/3815980/posts?page=430#430
Great minds think alike!