You had to have a clear objective, and work to that end, even when you were drinking sweat and pissing blood. If this sounds like macho posturing, that's because, in a way, it is. It's how Carol copes, by turning everything off, by being as stone cold as she can be. Whatever true grit is, this broad has it in spades. She's hurt and she's angry and she doesn't give anyone a break, least of all herself.
People are assholes.
This tale's fuse is lit in its first few pages when Charlie Riggio, a former colleague of Carol's from her bomb squad days, responds to a call and is blown apart while trying to dismantle a simple pipe bomb. Carol, next up in the rotation, catches the case. It's an uncomfortably familiar setting in which the ex-bomb tech finds herself. But she doesn't back down. This is her job now.