Warning: This article contains major spoilers from episode 6 of Andor.
Fans expected some of the rebels that Cassian Andor was working with to die at the hands of Imperials during the heist. The previous episodes spent a lot of time having the audience get to know the other rebels, especially Karis Nemik, Arvel Skeen, Vel Sartha, and Lieutenant Gorn, thus making their potential demises all the more heartbreaking.
What fans didn’t expect was that some of these rebels could die at the hands of Cassian.
After completing the heist and taking a gravely injured Nemik to a doctor, Skeen suggested that he and Cassian split the credits that they stole during the heist, run their separate ways, and leave their surviving comrades behind and without any of the credits. Cassian questioned everything Skeen said about the rebellion and about the brother he tragically lost to the Empire, with Skeen now claiming he had no brother and he is just a rebel out for himself.
It didn’t take long after that for Cassian to shoot and kill Skeen. Like many things in this series, Cassian’s motivations for killing Skeen, and whether or not the killing is justified, does not have a straightforward answer.
Part of the reason Cassian kills Skeen is out of self-preservation. Cassian does not trust Skeen and he has no reason to as Skeen has held a knife to Cassian’s neck, continually questioned Cassian’s loyalties and identity, and openly accused him of being a traitor. Cassian is also smart enough to know that someone willing to betray the people he’s been living and working with for months is just as likely to betray Cassian.
Skeen gives Cassian even less reason to trust him with his answer to whether the story about his brother was true. Cassian has been desperately searching for his sister for years. Losing her still haunts him and his desperate search is what kicked off the chaotic chain of events for Cassian in this series. Considering this history, any kinship that Cassian felt for Skeen disappears when Skeen says “I have no brother.”
It is left ambiguous whether this means that Skeen’s story was a complete lie or if it means the story is true–maybe Skeen did have a brother whose livelihood was destroyed by the Empire, but he’s dead now, and now all Skeen cares about is himself. It is also left ambiguous whether Skeen’s offer is genuine or if it yet another way of him testing Cassian’s loyalty.
Regardless of the truth, Cassian’s disgust for Skeen deepens further, especially with Cassian feeling that the loyalty and sacrifices of Nemik, Vel, Gorn, Taramyn Barcona, and Cinta Kaz mean nothing to Skeen. Gorn and Taramyn are dead, Nemik is on death’s door, they don’t know what happened to Cinta, and meanwhile Skeen seemingly only cares about himself.
Through these rebels, Cassian finally begins to learn what it means to be part of something bigger than himself, to trust and work with others, and to stand up for what is right in the face of oppression. These lessons will likely set in further with the manifesto that Nemik left for Cassian before his death. Skeen threatens everything Cassian has learned through planning for and carrying out the heist and he is a threat to the surviving rebels.
Cassian killing Skeen can arguably be seen as Cassian killing the selfish parts of himself that still remain, the parts that just want to run away with money, enjoy life, and not worry about the bigger picture of the galaxy.
As for whether it is justifiable, that is up to the audience. Cassian seems to think it was justifiable. By Rogue One, he may still feel it was a necessary but ugly thing to do, with the murder of Skeen being one of the many “terrible things” he’s done on behalf of the Rebellion.
Killing Skeen reminds the audience of how ruthless Cassian can be and how far he is willing to go to save himself, but it also demonstrates character growth, that he can be ruthless for something far greater than himself, and can rebel against his own self-interest.