From Halopedia, the Halo wiki
Walkthrough: In the level Requiem, after entering the terminus tower, one will enter a room where the structures hanging from the ceiling will retract into the walls on the side. At the far end of the room is a staircase that leads to the elevator which is the objective. The terminal is located under the staircase.
A ship coasts through space, approaching a fleet of human ships. A small craft scans the ship, which shows signs of Flood infection, and leaves. The main ship of the fleet charges its main gun and fires on the enemy ship, destroying it. Fade to the Ecumene Council chambers. The ship being destroyed is shown in holographic form.
The audience in the chamber cheer and applaud.
The audience cheer and applaud louder.
Fade to the Didact and Librarian stand on a ledge overlooking the Capital.
The two embrace.