I highly recommend all of the Retrograde stories, too. You probably already found the line by now, but it's in the conclusion (http://www.ltljverse.com/watergate/stories/recovery3.htm) of Recovery (http://www.ltljverse.com/watergate/stories/recovery.htm).

From Rodney's POV: "[Sheppard's] eyes were intent and very green and flat, like they got when he had been killing people who were too stupid to run away when they had the chance."