Missing the golden opportunity to kill Peter Pettigrew drove Sirius Black practically mad.
Now, with Voldemort's help, Peter Pettigrew had successfully turned into a rat, slipped down into the sewers, and vanished completely. Any anger Sirius felt now was entirely useless.
Felix Felicis told him that after causing such a massive commotion in the Dutch Ministry of Magic and still failing to trap Peter Pettigrew, the Dutch authorities might just lash out in humiliation and come after him.
Chapter 862