Metal Gear Solid V: Ground Zeroes - S-Rank Walkthrough - Classified Intel Acquisition (Infiltration)

Side Ops: Classified Intel Acquisition The key to earning S-Rank in this mission is obtaining the mission objective without interrogating the undercover agent. This will save you a lot of time which is rewarded with lots of bonus points. You can also get the Infiltration Trophy / Achievement during this mission. Just wait on the back of the truck in the beginning. It will bring you to the admin building. Go up to the watch tower (by using the ladder) and grab the cassette tape. Once you have the tape you can leave the area. The least risky way to do so is to get back on the truck that brought you to the admin building. Just stay on the back of the truck for a couple of minutes until the driver returns. He will then bring you back to the starting point which will end the mission and earn you the Infiltration trophy / achievement.