This answer contains spoilers… (view spoiler)[Don't you kind of like the ending though? Sam dying was a plot twist, I expected Boy Nobody to fall in love, confess and have the next book about them running away together. So I actually liked the ending, it kept me wanting to read what happens next . (hide spoiler)]
Taxandria Good going, Meghan. Just writing "spoilers!!!!" isn't enough to HIDE the spoilers you ninny. You just ruined the book for me. Geez. You could have alluded to the ending.
Mojoboy31 With the plot thwarted and the big bad taken care of, Sam's death wasn't operationally speaking necessary, but for Ben/Zach-- his assignment was also a test of loyalties. The Program needed him to kill her or they would never have trusted him.