Do I Believe that Xavier's Actions in Dying are Justified?

In the chapter Justified of Three Day Road, Xavier, after a long period of mentally struggling in a sense against his friend Elijah, has to make a hard decision. As they attempt to take a fortified line, their squad is slowly cut down by machine guns. Elijah, the highest ranking soldier, takes command of the squad, and orders the rest to provide covering fire for himself and Xavier and then retreat. Xavier immediately sees trouble in the near future, and as two heavy bombardments rage around them, they pick off Germans until Elijah turns to him, states while smiling that he "has gone too far" and then proceed to viciously attack and almost kill Xavier. Xavier, at this point is forced to kill him by choking him to death. This, I feel is justified seeing as it was self-defence, and though it may have been scarring, Xavier can at least know that he was forced to kill his best friend by circumstance, not choice.

K&E HWOL Number 1

            When the Canadians first appear at Vimy Ridge, they come under intense shell and sniper fire. I feel that Elijah and Xavier, arriving in France, would have been like those new recruits, naive and likely to be picked off by the waiting Germans. The new recruits would have to learn extremely fast, or else they would simply become another statistic in the killing fields. I feel the artillery would be the deadliest weapon, as it could do anything. You can fill a shell with explosives, cluster warheads, shrapnel, gas or anything deadly and nasty. Ergo, the artillery would be the harshest thing the Canadians face.