The 'Two Betrayals' mission in Halo: Campaign Evolved presents players with the opportunity to discover three hidden skulls and one terminal. This level immediately follows 'The Library' and tasks players with leaving the control center to destroy pulse generators, with collectibles available along the way.

Terminal: Alone

Upon starting the mission, players must first contend with four sentinels. After defeating them, turn around and follow the walkway to the far side of the holographic planet. The 'Alone' terminal can be found there.

Skull 1: Tough Luck

The 'Tough Luck' skull affects gameplay by causing enemies to perpetually enter a berserk state, dive evasively, and never retreat. To find this skull, players must commandeer a banshee to reach an upper landing. As soon as you exit the control center, head outside. A banshee will be parked in the distance near a wraith. Piloting this banshee past the objective marker's upper landing, towards a large Forerunner structure, will reveal a vertical beam of blue light. Landing on the section of the structure emitting this light will yield the skull. Be cautious not to fly too far, as a warning for going out of bounds will appear. The player in Halo: Campaign Evolved looking at the Tough Luck skull.

Skull 2: Black Eye

This skull, 'Black Eye', dictates that player shields will only recharge after successfully meleeing an enemy. After destroying the first pulse generator and proceeding outside, players will encounter three ramp-like structures and a conflict between Covenant and Flood forces. Navigate to the side opposite these ramps, where numerous Flood growths are present. The 'Black Eye' skull is hidden within these growths. The player in Halo: Campaign Evolved looking at the Black Eye skull.

Skull 3: Mythic

The 'Mythic' skull increases enemy health. To locate it, continue following the main objective marker until you reach another large open area with paths to the left and right. This area is identifiable by a significant battle between powerful Covenant and Flood variants. Take the banshee parked on the ground to the left. Fly it upwards and land on the platform above the central rock. After eliminating the enemies present, interact with a console to open a door on the platform opposite your quest marker. Obtain another banshee and fly to this newly accessible platform, entering the structure. Clear out all enemies in the first room, then use the console to proceed through a door into a tunnel. Continue through the tunnel and the subsequent room, defeating all foes, including stealth elites and hulking Flood enemies. The 'Mythic' skull will then spawn on a pedestal in the middle of the second room. The player in Halo: Campaign Evolved flying a banshee.