As facts proved, those who have truly experienced life-or-death battles and seen blood are vastly different from ordinary young wizards. Take Lupin and Sirius Black, for instance; both of them were far more decisive and ruthless in their choice and execution of spells.
If it were young wizards like Harry, their opening move would typically be utility spells like Expelliarmus or Stupefy. Unlike them, Sirius and the others started right off the bat with Sectumsempra, while Lupin followed up with a Petrificus Totalus, completely cutting off any possible escape route for Peter Pettigrew.
Yet, it had to be said that Peter Pettigrew truly lived up to being a "rat" who had cowered and survived for so many years. While his mastery of magic wasn't much to speak of, his ability to flee for his life was formidable.
Chapter 182