Here is the transcript of the New Interview of Rob with RTL in their program "Laisser Vous Tenter"
It's Robert Pattinson who is playing amazing this low mind
Rob: He's always been treated as someone who has a low mind by all the people surronding him so he never had to take any kind of responsability. it's the same thing when he kills people. For him it's not real. He doesn't understand what's happening and it's like a game. No one is nice towards him so since no one takes care of him , he doesn't care about anything. The importance of killing someone doesn't matter
At the end of the interview, they said Rob could play in another saga. he could play a younger version of Indiana Jones in the 5th sequel.
But this info is to be taken with a grain of salt