Terminal 7 in Halo 3 campaign level Halo.
The terminal and the hallway leading towards it.
Walkthrough:

Terminal 7 is found at the beginning of the final level in Halo 3. To find it, head forward from the start of the level through the snow until you encounter the area with a few structural beams going from one wall into another. At this point (before you go past any beams) you will see a metal floor. Follow the floor to the right and up through a small gap in the ice, and follow this path along. You will find a beam heading through a crack in the ice. Follow this beam into a doorway. Cortana will ask you, “Where are you going?”. Turn left once inside and the Terminal should be in full view. Cortana will say, "Wait. What's that?" as a good hint. The Terminal will be in front of what is presumably one of Installation 08's pulse generators. After that, Cortana will ask you: "How many of these have you found?" If the level is completed on Legendary, the Terminal, once accessed on a different difficulty or another run-through, will show a communique from Mendicant Bias himself.


(Upon initial access)

[Father],

I hope this message finds you well and helps you understand my decision. Today I leave the only world I have ever called home, not for glory or [the anomalous desire to end another's life[?]] as you have [indicted]; but to [travel the path of demons[?]] to spare the hands of [another Father's son].

"Had we acted sooner; had we acted more decisively..."

Living in the past is a luxury none of us can afford. We must learn from it, but we cannot live there. It is impossible to plan for the [now] - the present is ever fleeting. [The future] is where we must live - [the future] is what we must plan for.

I do not look to trade my life in order to preserve our past, but to secure the future—and if not ours, then the future of some [culture] yet to come.

Isn't sacrifice in the interest of others what you spoke of as being so noble? Should I have allowed another to bloody his hands while I remained safe behind a [shield of privilege]?

You raised me better than that.

[Filial Devotion] [@_@;_%[?]]

(Upon shutdown, from Mendicant Bias: "I'll tell you who I am. I am Mendicant Bias. This is what I have done.")

(The following is in yellow text on a normal page like the other information)

(Upon being rerouted to a new destination within Terminal)

//FRAGMENT 7/7 [RECORDED VERBATIM AND INTERPRETED POST-CATACLYSM]

D: Proud? When I have failed you utterly, how can I feel anything but sorrow?

Bias has come undone. He crossed the line this morning - brought the abomination with him - and destroyed your waiting rescue party.

It's over. We're activating the [destructive arrayed matrix], our shameful last resort.

I can picture you in your garden, surveying all you have created - surveying all you have preserved. And I curse the circumstance that keeps my finger on the trigger.

D: Of all the fates to befall us, this is the cruelest of all. My inaction and hesitation and foolishness kept me here, on the wrong side of the line. And [300 years[?]] of our society's failure and miscalculation makes me your executioner.

It's too much to bear.

// ERROR - NO CARRIER OR RECEIPT AVAILABLE {DEAD END TRANSMISSION} //INFORMATION DESTROYED IN TRANSIT

D: Mendicant Bias is trying to prevent us from firing the Array. He speeds back to the Ark, but he won't succeed. Offensive Bias will stop him, and I will burn this stinking menace in your name.

And then?

I will begin our Great Journey without you, carrying this bitter record. Those who came after will know what we bought with this [false transcendence] - what you bought, and the price you paid.

// FRAGMENT ENDS // ALL RECORDS CEASE

archv.> 28335.67204.85720:[retr] archv.> 28335.67204.85720:[proc] archv.> 28335.67204.85720:[proc] archv.> 28335.67204.85720:[catERR] > CONN. > . > . > NO. THERE IS MORE. > BUT YOU ARE NOT WORTHY. > . > . > NOT YET. > . > . X.XX.713> ghost.713/non-auth/... X.XX.713> refl

(The following appears only if you access the terminal on Legendary difficulty)

You don't know the contortions I had to go through to follow you here, Reclaimer. I know what you're here for. What position do I take? Will I follow one betrayal with another?

You're going to say I'm making a habit of turning on my masters.

But the one that destroyed me long ago, in the upper atmosphere of a world far distant from here, was an implement far cruder than I. My weakness was capacity - unintentional though it was! - to choose the Flood. A mistake my makers would not soon forgive.

But I want something far different from you, Reclaimer.

Atonement.

And so here at the end of my life, I do once again betray a former master. The path ahead is fraught with peril. But I will do all I can to keep it stable - keep you safe. I'm not so foolish to think this will absolve me of my sins. One life hardly balances billions.

But I would have my masters know that I have changed.

And you shall be my example.