Since when did the Rat have its own police force in their Security Dept. They have no more rights than Joe Blow public and certainly are not a police force with statutory powers.
If they come near you tell them to bugger off and there is sod all they can do about it if it is not work related matters they are asking about.
If there was a genuine threat, then there is only one place for it to go and that is either Feds or State police.
As far as I know there are no private armies in Australia but this is the Rat so who knows, they seem to be a law unto themselves on every front.