I don't think anyone ever gets used to watching people die. You might get de-sensitized. But in the long run, I feel that it affects you negatively no matter what.
Of course it does, but I believe that's how it's supposed to be.
I understand why they(devs) made all the stuff to Chris - to make him more human et cetera... (I actually approve the idea, though I despise it's realization in this game) Thing is - in reality any soldier who will act in that manner(especially the ones in charge) would be sent back home immediately, without the chance to ever be reinstated.
I know that it's just a video game chars and one shouldn't judge them as if they were real people... blah-blah-blah...
I'm just bored at work so I'm giving my thoughts/opinion on the matter that's all I never said that my word is gospel of holy truth, right?))
To wrap this up; Piers turning into a J'avo obviously gets most votes by far (again kudos to Capcom for making compelling moments) followed by Lisa Trevor and Helena's sorrow (that struck us because of amazing voice acting).