Hey
I personally think that the file no. is just for reference as to coordinate between different disciplines. Like for example when you send your passport back after you have done your medical, the file no. directs it directly to your documents and same is with your medical reports.
I dont think it has anything to do with acceptance or rejection.
Also, if they have to reject at that stage, they dont ask you to take your medicals and reject your visa application.
Its just what I think. I hope you are correct! haha..