WARNING: Spoilers are unmarked.
- John running into Kyle and asking for his name. When he learns he's the Kyle Reese, John lowers his gun in a subdued and wistful Oh, Crap!, because he knows that this young man will become one of his greatest friends, and that in time, he will have no choice but to sacrifice him to save the world.
- Marcus' reaction to finding out that he's a Terminator is truly heart-wrenching. This is a man who was rightfully convicted of murder, a man who wanted to redeem himself by dying and giving his body away to science. When he turns up in the future alive, he thinks he's been given a second chance. But then he finds himself in the middle of a war between man and machine. He does what he can to help the remaining humans and even tries again to redeem himself for murdering his brother by protecting Kyle Reese and Star, two youngsters he has just met. Then things go downhill. Kyle is captured by the machines and Marcus gets captured by the Resistance. To make matters even worse, Marcus is revealed to not only be part-machine, but a prototype of a new line of Terminators. Machines whose only purpose is to kill.
- After learning he's a Terminator, Marcus is allowed to go to Skynet's San Francisco base in order to help the Resistance get Kyle back. By this point, he is now more battle-damaged, with more exposed machine parts. As he leaves, John asks him "What are you?!" Marcus, who earlier asserted that he was a human, simply responds with a dejected "I don't know."
- When Marcus approaches the facility to allow one of the behemoths to scan him and it allows him in, he closes his eyes sadly, probably half-hoping to be rejected as human and not allowed in as a Terminator.John: They know what you are, even if you don't!
- While chained to the cross in the missile silo, Marcus is callously used for target practice by Barnes, who shoots him on his exposed endoskeleton with a bullet for every dead comrade he has. Marcus endures it stoically, without letting out a single groan or even merely looking at his tormentor despite the evident pain. But when Blair comes to relieve Barnes and she coldly joins the shooting game, Marcus can't take it anymore and screams in agony. This is the point in which Marcus breaks up. He can take the hate from these men who have condemned him for being what he is (something which horrifies and scares even Marcus himself), but not from Blair, the only person in his terrible world who gave him a warm smile and an opportunity to leave behind his old self. He realizes that there will never be hope for him.
- Marcus offers his human heart to save a critically-wounded John.Marcus: Take mine. You said every man gets a second chance. This is mine.
- His speech:Marcus: What is it that makes us human? It's not something you can program. You can't put it into a chip. It's the strength of the human heart. The difference between us and machines.
- His speech: