I was referencing the marines that were at the burial service cut scene. I know what I said suggests other wise, but this is what I meant. And I haven't actually read Glasslands.
You are all forgetting about The Arbiter and the other marines that got through the portal and made it to Earth. What if they are still on Earth and they are trying to find a way to get to the Chief? The could use the artifact in Peru to try to open a portal. What do you think?