Some people have asked me, if you should scream at an attacker. For me, it's like a no, no situation.
You should never ever scream at an attacker because you don't know that person, you don't know if that person is going to become angrier or not. But let's put just a very simple example like, let's say that I have a knife, I'm going to be nervous, not because, you know, I have a knife, I'm going to be very safe you know, I'm going to feel threatened because it's a real danger situation, even if I'm the one weilding the knife.
So, if I'm nervous and you scream at me, I might react by going away and stabbing you by accident, that's one of the cases. The other case is that you scream at me and I'm not afraid of you and you just made me mad, like very very mad. I'm going to hit you harder. So that's why you should be calm, assertive definitely, not be scared, that's the only thing that you shouldn't do, don't be scared but assertive. Say, 'Okay I got it, don't worry I'm going to give you my wallet or whatever it is' but never never scream at an attacker.