Shinji feels a chill go down his back. He thinks, "I almost killed human beings, and people I know, at that…"
Reichu: Heh, if Shinji were someone else, he might have been thinking, "Cool! I almost killed that bastard who beat the crap out of me!" Despite Shinji's rather antisocial nature, he has a remarkable innate concern for human life. (Not that he would let it serve as any kind of primary motivation for piloting the Eva or anything…) As we'll see for the first time here, he actually will sit there and take the burn from an enemy if he thinks someone is endangered by taking aggressive action — although, the next time this happens, he really lets sentiment cloud his judgment. (Considering the true nature of the Angels, that Shinji is this way is kind of ironic, really.)
tv33: "Innate concern for human life"? Well, just don't bring up EoE…
Reichu: SHHH! We'll cross that bridge when we come to it. ;;>
Incisivis: I'm going to side with you, Reichu, and say that in this case, he's motivated by compassion. As for Shinji as a whole… I think worrying about his reputation and his low self-esteem plays a role in some of his "compassionate" gestures, but to attribute them wholly to Shinji's faults is oversimplfying things. EoE is more, "Well, he's snapped," than "Oh, he was always like that,".
HeWhoPostsStuff: I tend to think that he just doesn't want the weight of having killed another human being (i.e., someone other than himself) on his conscience. I figure that Shinji wouldn't particularly like the idea that he was responsible for killing anyone, especially considering his reaction (or lack thereof) when he faces Toji in a slightly more intense situation…
Reichu: On an aside… What's with the funky red background and lighting here?
Hexon.Arq: Blood was very nearly spilled! Well, human blood. Well… okay don't go all technical on that now. ;) Color and lighting for intensity; red for… well, blue wouldn't have fit.