2. The Moral Decisions
"The needs of the many outweigh the needs of the few." The famous words of Spock ring true for any scenario involving making a choice for the better part of the whole rather than for one's self. Thus is the way of choosing to save someone's life in exchange for your own, sometimes multiple people. But the implications go beyond that; in the case of "Sunshine", we have Searle who makes the decision to stay behind on the Icarus I so that Capa, Mace, and Harvey can take the chance to go back to the Icarus II. Searle was one of the more patient and unsung characters of the film, for he had a fascination with the sun and always spent time in the observation deck of the Icarus II examining the sun's rays and brightness. So when deciding to stay behind he finds the Icarus I's observation room and makes the ultimate decision to....."open the blinds" so to speak, incinerating himself from the full effect of the sun. Now what made him do this exactly? One of two things: the lack of oxygen would have eventually killed him if he spent too long inside the ship investigating, so he knew the only way out was to witness the effects of the sun for a quick way out, or he wanted to experience the majesty of the sun and feel the pain that the Icarus I crew felt. Self-sacrifice plays a pivotal role in the drama of the film, with various crew members giving their lives so that the others can move on. Kaneda and Mace, the two tragedies of the crew, gave up their lives so that the mission could prevail. Kaneda was successful in fixing the shield only because he had no other choice in the matter, so he accepted his fate and continued making repairs while the sun's rays inched their way around the shield, burning Kaneda in the process. Seeing as how Capa was high priority for the whole mission, Kaneda ordered him back inside the Icarus, inevitably saving his life and everyone else.
Mace, after having a disillusioned Pinbacker cause considerable damage to the ship's mainframe, dives into the coolant hold where the mainframe is housed. By doing so he was restoring power to the Icarus, allowing Capa to move forward to activate the payload. After enough dives in the coolant Mace dies, but dies a valiant hero just like Kaneda because they made the moral choice of putting their lives on the line to preserve the mission. Morally these two men symbolize the heroics in humanity, showing that in the darkest of hours there is still a light at the end of the tunnel....even if it requires their own lives to pull the curtain hiding that light.