The American official translation of "The Management of Savageness"

I have not read the American official translation of "The Management of Savageness" by Brookings' William Mccants (and the task is not easy: it is quite difficult to translate) but this passage in the account by David Ignatius Al-Saud struck me:  "In another passage, he notes that “we need to massacre” others as Muslims did after the death of Muhammad." In the original passage the author uses the word "Ithkhan" which does not mean massacre but means "heavy combat" or "intense killing", in fact. As for the book, its influence over ISIS is quite exaggerated in my estimation as the author (I personally think he is an Egyptian) is more concerned with PR and public opinion than ISIS is.