Stasis is achieved by the "farm" imposing a set of ancestral lineage constraints upon the human life "experience". These frequency patterns are recreated upon each level of said lineage. In lay terms these are "culture", "ethnicity" and "nationality". Humanity are segregated into these different stasis models which are then altered as and when required in order to yield a stronger "harvest". 

In order to move out of the constraints of these base stasis models the 144.000 have to be cleansed down to DNA/RNA level thru a process that sees them wipe clean the foundation of the human physical vehicle into which they have incarnated. This is done within phase one of the process and must be completed in order to exit phase one and begin to enter phase two.