Howling:Why are robots attracted to the "Promised Land"?

So, in Deep Breath we see that the Clockwork Droids are searching for the Promised Land. Which, at first, seemed to be superstitions caused by their use of human parts and how long they've been stuck - until the first scene with Missy. Then, in Robot of Sherwood, we see more seemingly unrelated robots headed for the Promised Land. This made it look like this "Promised Land" was a physical place somewhere. Then in Dark Water, we find out that the Promised Land first seen in Deep Breath is a part of the Matrix from Gallifrey. So why do you these two (possibly more) groups of robots are trying to get there, and how does Missy/"The Mistress" tie into this? --Thecrazyweirdo (AKA CommanderAwesome) Talk  Contribs 01:56, November 6, 2014 (UTC)