I think the entry for Gameplay and Story Segregation is missing the point on what Rafe meant by cold blooded killers. Yes, Nate and Sam killed a lot of Shoreline mercs but those same mercs would have killed them if they hadn't. Nadine at that moment was a hostage and not capable of defending herself. So, killing her like that would be cold blooded. It is clear that Nate at the very least isn't willing to go that far.
I think the entry for Gameplay and Story Segregation is missing the point on what Rafe meant by cold blooded killers. Yes, Nate and Sam killed a lot of Shoreline mercs but those same mercs would have killed them if they hadn't. Nadine at that moment was a hostage and not capable of defending herself. So, killing her like that would be cold blooded. It is clear that Nate at the very least isn't willing to go that far.