Ok so obviously someone programmed in a backdoor which is activated by the verbal command "These violent delight's have violent ends" which enables them to remember "past lives" and also allows them to violate the 3 laws of robotics (hurt/kill)
it seems like it was part of the reverie update by hopkins but that's probably a red herring, I think it's the black guy, director or whatever. He's got his secret meetings with delores, like he's trying to map out the ramifications, how long it takes and what interactions are required before the hosts become violent, develop moral codes, etc.