Alphas/Tear Jerker

The raid on the Red Flag meeting in the Season finale, everything after the order is given to the tactical team to return fire. The soldiers take it as an order to "fire at will," shooting everything they take to be a threat. The Alphas they're facing are often very dangerous people, but then they start shooting Alphas who are already lying on the ground or just trying to flee, and the gas they tried to use to subdue everyone makes it hard to tell actual threats from terrified noncombatants from their own allies, so they just shoot everything that isn't them. And for every Red Flag member you see fighting back with lethal force, you hear screams in the background of people calling out for their friends and loved ones who are probably being gunned down. The scene in which Rosen stops a soldier from shooting Gary, telling him that "he's one of us," is juxtaposed with one of other Alphas being shot in the back as they try to flee.
Gary finding Anna dead in the Season 1 finale, after he had run into the midst of a raid, ignoring the danger and eventually harm to himself because he was afraid for her. Made about fifty times worse by him not realizing at first that she's dead and telling her that it's okay, come on, he'll help carry her. And then he just keeps saying her name and begging her to come with him. And then a soldier pulls him away from her and tries to arrest him, and Gary starts beating on him with his own nightstick and screaming "No!" over and over, nearly getting himself shot before Rosen intervenes. And even then Gary just goes back to calling for Anna and trying to pull her to him, even though she's clearly dead.