Brian must think Tyson never had a street fight on concrete growing up on the streets of Brooklyn. 
lol - Brian is too young to remember Tyson in his prime and the stories of how Cus saved him from the streets by training him.
But Brian knows more than the tons of TOP level fighter / wrestlers / grapplers etc who have all said they would not like to have to fight Tyson in a “no rules brawl”
The truth is Brian knows that he is safely away from Mike / Josh / 38 / YOU etc etc
Brian was terrified of Josh - and in the weak mindset of Brian the way to deal with that fear is to TALK and talk and talk - then do whatever it takes to make sure Josh couldn’t come get him.
Brian - if you really believed you could (murder death kill) Josh he wouldn’t have EMAILED (cause he loves to say he never CALLED) the police. And if he was SO confident that Josh was not even going to try and come beat his ass then WHY would he have contacted the law?

? It’s illogical