This is exactly how I imagine Loki. He really is a good person/old Loki deep down, but something inside of him comes out and takes control. You can see it too, like when Thor and him are on Stark tower and he sort of 'steps back' and you can see it on his face how scared and disbelieving he is. But then the other side of him takes back control and he stabbs Thor. Thus the never ending battle continues.