Though there are no obvious controls on the VIS that offer a manual safety, I noticed that when the hammer on my VIS is at a 1/2 cock, it locks the trigger and acts as a manual safety (much like my 1892 Winchester replica).
Though nothing I've ever read about the VIS suggests that there is a manual safety, the design makes sense with knowing that this pistol was originally designed for use by Poland Calvary.
At a 1/2 cock, the hammer is relatively easy to bring into a full cocked position with the thumb or maybe down the pants leg by a solder in the Calvary.
It may even be designed that way to pass some sort of drop test. I don't know.
Can anyone tell me if this was the intent of this design?