What happens if you Ctrl+C, Ctrl+V on the Doctor’s data files? Do you duplicate a sentient being?
In “Virtuoso”, Tom & Harry try to reproduce the Doctor but they’re basically trying to make him from scratch, so I don’t think their failure is relevant.
At the end of “Author, Author” we see many repurposed EMH Mk1s working as miners:
…and they seem to be self-aware, so I guess we have to assume that it’s technically feasible.
But then what happens if you Ctrl+Z?
Well, no. Subjectively either the observer is continuous or it isn’t. Either you walk in one end and walk out the other continuing to perceive your body and the world around you, or you’re replaced by a different perceiving entity with the same memories.
Certainly the speed at which your body is deconstructed might have an effect on the pain and horror of it all, but in terms of your consciousness remaining afterward it kind of either does or doesn’t. If some other consciousness is looking through your eyes because you own has been extinguished, it’s not going to do you much good if it just happened fast enough that it doesn’t have to grapple with the memory of disintegration.