For a second there, I thought he killed you after killing Eric. But he was actually addressing Cooper and killed him to end his suffering. Afterwhich, the man shoots himself to end his own pain. He was tortured and can no longer go back to how he was, and therefore, his last comfort was saving you and knowing that he's still human, even in his final hours. Interesting game. It started out with a wacky mechanic, but the dev added a nice touch for a story at the end.