I had thought the same thing but you would have thought that someone would have seen this happen other than the vet himself so keeping it quiet would be a tough thing to do. Regarding giving the dog to someone is a possibility but I couldn't think why he would risk his reputation by doing this.
I personally believe that she got loose and ran. But my impression would be that she would steer her way toward Philippe and William's home and based on the distance between the 2, it would take her some time to maneuvre the mountains and roads and depending on how many people actually live between these areas, might be hard for someone to actually detect.
When we moved from our apartment to our current home and had a small Yorkie called Harold, on the first outdoor walk that we made, he actually began to trace his way back to the apartment and so I do hope that it is my last thought that is the truth and hope that eventually she does find her way back. Dogs have an amazing sense of direction and when they have a will, they'll find a way to at least return to the same area from where they lived.
Life is not a child's game of follow the Leader. Instead, life is more about finding one's own purpose in life....your life's plan, and then making a positive difference on earth.