It may take several more weeks for him to fully comprehend and appreciate the advancements of medical science, but even in his largely dazed and disbelieving state comes a small sense of wonder at how advanced the civilization of Panem is, how long the world has come from their own time. not that he had even been aware of the cholera outbreak though So when Enjolras brings his hand to his neck, Marius wonders whether it's related to the way he died, if something had been there before he was brought back. But asking outright is one of the last things he will ever do and so he simply says, "I am sorry."

A belated response to the news of Enjolras dying, but maybe Marius is also apologizing because of the guilt stemming from his thoughts—the idea that he finds it impossible to separate the correlation of Enjolras and death, as if it always follows him around like a shadow.

But he believes that Enjolras will always find something else to fight for, some grand idea to die for. Even here he doubts that Enjolras simply accepts that he has little choice but to fight in the Hunger Games and that nothing can change. As for himself, he is all the more willing to die for a cause now that Cosette is gone and his life no longer has meaning. So without the smallest tremble in his voice, he asks, "What must I do?"