You arrive in the control room of Installation 08, the newly-forged, incomplete Halo. It's spacious, with a huge hologram in the centre showing the ring in its entirety, in the centre is the main control terminal. You have the Index, and plan to use it to activate the ring. With Installation 08's activation in its incomplete state, it will likely destroy itself as well as the Ark that is creating it, and then no more of these superweapons will be made. As you approach, a metal sphere with a blue light descends in front of the control panel. This must be the 'Monitor' you were warned about... 343 Guilty Spark. Upon noticing the Index in your hand, he quickly begins to protest.

"But, but, but... a premature firing will destroy the Ark! Will destroy this Installation..."

But as you move to insert the Index despite Guilty Spark's warnings, his light suddenly turns a deep red, and he shoots a powerful beam of energy from it, knocking you to the ground.

Unacceptable! Unacceptable! Absolutely unacceptable! Protocol dictates action! I see now that helping you was wrong!

As you try to stand, he uses a second beam - you collapse again; the pain is immense, although momentary. Guilty Spark floats towards you slowly, staring you in the eyes with his crimson light.

"You are the child of my Makers. Inheritor of all they left behind. You are Forerunner. But this ring..." IS MINE.

A shockwave emanates from his core, pushing you back like an intense current of wind, far stronger than you can resist, followed by another laser which narrowly misses you. You realise only one of you is going to leave this room alive.

You do not deserve this ring! I have kept it safe! It belongs to ME!

Your mission is clear. Kill the Monitor. Activate Halo. Escape.