The Jetstream DLC ending. The content itself doesn't hurt, but when you listen to "The Only Thing I Know For Real" again... everything starts to make sense about Sam's character. Fridge Brilliance and Fridge Horror kicks in a lot when you look over "Collective Consciousness" and Armstrong's cutscenes.
When Armstrong extends his hand toward Sam and welcomes him to the team, Sam looks down and starts laughing... but the way his shoulders shake and his facial expression makes it look like he's weeping because he just had the last bit of hope crushed from him.
There's something about the way Bladewolf pleads for you to stop attacking him just before you finish him off in his battle. He barely has his own life, but he doesn't want Raiden to take it away. Thankfully, Raiden has Doktor fix him up later on.