Blood Work ending explained (spoilers)

[kylie]

Buddy is the Code Killer and the one who killed Graciella's sister and the guy at the ATM machine. Those victims were part of his plan for Terry McCaleb to get the heart transplant (since the two victims were the same blood type as McCaleb). When McCaleb figures out that Buddy is the killer, Buddy tells McCaleb that Graciella and her son are hidden somewhere. McCaleb shoots Buddy and forces him to tell where the woman and son are being held. They go to an abandoned boat. On board, McCaleb and Buddy trade some words, chase one another in a storm of bullets. McCaleb finds Graciella and her son. They board McCaleb's boat. McCaleb kills Buddy.