Halo* Co-op Partner Required *
At the very beginning of the mission, continue forward for about 1 minute until you notice a structure in front of you. Before going under this structure, head right where you will notice a small door in the cliffside. Once inside the door, you'll have to do a co-op jump across the gap to the right hand side.
One person should stand near the edge, as the other stands on top of them. Have the bottom person do a running jump into the gap, and then the top person will have to jump off their head at the peak of their jump to land on the pillar. Wait until both players are spawned and then take turns trying to jump from this pillar to the left hand side. Once you make it into this new area, go into the corner and use your flashlight to find a half-naked dancing man who is Jason Jones co-founder of Bungie. Look at it to get the achievement to unlock.