...I realize this is your first stint as a soldier, so, I'm just going to lay this out there.

When you're on the battlefield, the past doesn't matter. You don't need to know anything about the person by your side beyond the fact that you're both fighting to keep the other one alive. This means a lot of us carry some serious things close to our chests.

Now add to that that you're a mercenary. The people you work with today could easily be the people you have to kill tomorrow. There's nothing you can say about this sort of work: we're on contract for Martian independence during this war, but, maybe next time we'll be on the side of the colonies, or even the Lunar forces. It's the nature of the job.

[He shrugs.]

There's no bigger point to this. Hide what you need to, and tell what you have to. It's the only way you'll stay sane in this line of work.