To do this glitch go to the Covenant.

After you've disarmed the third tower go to were the hornets land and take one.

Immediately go to where the scarab lands on the right side (there will be a black spot), the scarab should land there before you get there so as soon as the scarab lands go and jump out of your hornet and land right below the head.

Then jump on the top right leg before the scarab starts to move.

Then go to the very edge of the knee. Then when the scarab moves their leg you'll rocket up above the playing space and the Chiefs body stretches.

Then in theater mode you can fly around outside the playing space, but you have to do it right when the Chiefs body stretches and you can take some screenshots.