While being interrogated about the Khe Sahn mission, the voice of the interrogator is noticeably softer than it usually is when noting that you risked your life to rescue Hudson, when he was knocked unconscious by the Jeep crash. Since Hudson is doing the interrogation, this shows that he is still very grateful that you saved his life.
Hudson, asInterrogator: Hudson was down, and Khe Sanh was under siege. But like with Weaver, you risked your life to save him.
Mason: Hudson was a fucking ice cube. But that's why I liked the bastard.
"Mason! You did it, Mason! You did what I could not." And so, Reznov's soul can finally find peace.