You would only deliberately release it...if you had the vaccine that works. China hasn’t proven that they have that magic vaccine.
Course, there is the other scenario that some antigovernmental people in China got fed up with the system, and figured ‘what-the-hell’...let the virus take down the government.
Well if Felonious Van Pantsuit had won in 2016, they would not have had to start the plan early, its all Trumps fault.