Stargate Atlantis Season Four

I just finished watching Season Four of Stargate Atlantis on DVD, and once again I was very disappointed that the writers decided to bring back Dr. Beckett as a clone. First of all, how was Dr. Beckett cloned and in what time frame, that was not even explained to us? It could have been a lame explanation like a tank with special liquid or whatever. Yet, he was an adult with all of the original Dr.Beckett's knowledge and memories and skills as a medical doctor. The clone thought he was the original Dr. and had been taken prisoner and held captive for two years until he was finally rescued by the Atlantis team. How in the world did Dr. Beckett get cloned, develop into a baby,then be born, grow into a mature adult in such a short time, then get retrained as a doctor and have all the memories downloaded into his brain? Even if I decided to ignore the silly clone business, I feel bringing back Dr.Beckett at all took away from the episode entitled "Sunday" in which he died. I though that episode was very well done and very sad, it was one of the better episodes I had seen on Atlantis. So to bring Beckett back in such a cheap manner for me took the wind out of the sails on the "Sunday" episode.
Of course I still bought the Season on DVD and I enjoy watching and re-living the Atlantis experience again even though I have problems with some aspect of the series each season but then again I am a die hard fan. If you love the show it is worth having it on DVD.