Halo Easter Egg - The Nipple Grunt

Most Halo veterans will already know this, but there is a hidden grunt, who says something along the lines of, "Good thing that food nipple's waiting back on the starship, 'coz man, have I worked up a big, grunty thirst!"
1. Get to the jeep dash part at the end of the last level. After the dropship flies past, a new checkpoint appears.
2. When the distance to that checkpint is at about 915 metres, there should be an open door on the right. Go down it.
3. Halfway down the tunnel, there is another door on the right, with another tunnel full of dead stuff. At the end of the tunnel is the grunt. Walk up to him to make him say the message.
This is not the only egg in the jeep dash part.
1. Further on from the grunt, you must drive the jeep down over a cliff, to a safe landing spot below. Aim to the left or right a bit, & if you get it right, you can walk over to a bridge above the bit where you would normally land. There is a small room on either side of this bridge.
2. Go into the room on the right(the direction you would normally go). On one wall, the word REX is written in blood. The level's designer, known as Ferrex, or Rex, put it there.