As I imagine it can hardly be in the lab because the lab itself is not a good environment for the virus to spread. However if only one sick transfers it somewh

As I imagine it can hardly be in the lab because the lab itself is not a good environment for the virus to spread. However if only one sick transfers it somewhere it spreads in the environment where it is easy to spread - smaller (semi) enclosed space, a lot of people in that space, particular humidity and etc. E.g. if I got a virus in laboratory and then spread it on the plane carrying 200 passengers, the first outbreak would be on the plane. However we can't say it "originated" on the plane.