The First Kill

In the Chapter Raiding Party(pg62-75) Xavier and Elijah get into a predicament which causes them to have to throw two mills bombs into the crater they hid in all day. This is both of their First human kills, and it seems to be affecting Xavier more than Elijah, " I replay it over and over in my head so that i don't sleep all night, pulling the pin on my mills bomb, throwing it and watching it arc until it disappears into the crater, the concussion and screams. I have killed someone now."(Pg75). This shows that he isn't ok with it, he did not like it. There is a part right after that makes me think this, it is when Thompson went to Elijah and Xavier and asked "What do you think of the last days, Whiskeyjack?"(Pg75), he was only asking Elijah and he said "It's in my Blood" then walks away without asking Xavier, this possible means that he know he wasn't ok with what he has done.