After the scenes, carry Hudson to the tunnels. Go out to the trenches and clear the path.
Objective: Defend Khe Sanh
Objective: Clear the trenches
Continue along the trenches and a Vietcong will jump unto you. Press X rapidly to fight back and plant a grenade on the bastard. Continue along until you reach the defensive line.
Objective: Hold the line
Enemy infantry is flooding the area and you need to use the detonators to halt their advance. To find the first intel of the mission, run along the trenches past the two detonators and go uphill to find the ammo caches. There intel is located among them.
SOG Intel 1/3
Back to the action; wait for the enemies to form around the line before using the detonator for more kills. After repelling the foot soldiers, T55 tanks will arrive. Enter the gunner shed to the left and grab the LAW. Use it to destroy the Russian tanks. After destroying the tanks, follow Woods and Hudson to the next part of the base.
Objective: Push back the NVA
In the next part, more NVAs will attempt to break through. There are two napalm barrels here which you need to puncture and push to the trenches. Carefully approach them and kick them to hold off incoming forces. Another intel is located inside the pillbox to the left. Refer to the video below.
SOG Intel 2/3
Objective: Retake the hill
Head to the next objective and climb uphill as you kill enemy forces. After reaching the hill and saving Woods in the nick of time, continue to the tunnel. Inside this makeshift command post is another intel. Refer to the video for better directions.
SOG Intel 3/3
Objective: Get on the jeep
Head outside and ride the jeep. You need to use the mounted TOW missile launcher to destroy all six tanks. Remember that you can steer these as well. If you want another achievement, you need to destroy the tanks without missing. See the achievement section for the video and more details. Destroy all tanks to complete the mission.