Well, as far as I'm concerned, I thought killing Caruso while he's watching his homemade videos was depressing. He's just so sad, it's deflating.
I didn't remember the line "I can do anything I'm paid to do", but I think it's nicely ambiguous. It can imply he does whatever as long as he's paid, or that he doesn't have to do something just because he's paid or that he can't actually do anything unless he's paid, all at once. It does sum up his character nicely, in a way.
This comment by 47 from the cutscene at the airport got me wondering, as well:
"A Shadow client? Someone was rich, the contract was just. How is this our problem?"
He's doesn't say the contract was "paid", "legitimate" or "in order", he says "just". So I guess he does care about justice?