I only read that passage last week, and John hides a nice twist here: He has Kaiphas saying that "it is better that one man die for a whole nation", and John then explains that this was accurate prophecy, as Jesus would die for the nation and indeed all of mankind; and that Kaiphas was able to do accurate prophecy because he was in cathedra as High Priest at the time. I guess the musical sort of plays on that by having Kaiphas emphasize his "perception", but a chorus of "let him die for everyone" or something like that would have emphasized the dramatic irony better, I think.
