This is one of the shortest mission of the game. You will only have to secure three rooms. There is also one civilian here. You will have to rescue him in order to be able to proceed with the third mission of the chapter. You should be able to finish this level within about 5-6 minutes.
Your first objective will be to reach a nearby door. Use the stairs to get down to a lower level (#1). You won't encounter any terrorists here, so you don't have to hide. You will come across a single door. Use the camera. Tag two opponents. One of the terrorists will be standing in front of you (#2). His colleague is to your left. He is standing near the window. Order your men to proceed with the assault. I would recommend using explosive charges here.
Enter this room quickly and stand in front of a small door. A third opponent will try to enter this room. You will have to take him down quickly (#1). You may proceed to the next section of the map. Open a door and take out a single terrorist. He should be standing to your left (#2). Go back to the previous room.
At least one enemy soldier will be hiding on a lower floor. You could try and hunt him down on your own (#1), however I would recommend sending your team to the next room. Either way, he must die. Head on to the left door. Sadly, the staircase is going to be guarded by a single terrorist (#2). You should be able to kill him from here. Once he's gone, head on to the lower level.
Keep moving forward. A single door should be located in front of you (#1). That's where the innocent civilian is being held. Use the camera and tag two terrorists. One of them will be guarding the hostage, so it's very important that you target him (#2). Order your men to prepare for an assault. Head on to the right door. It's not necessary, but will increase your chance of a success.
Proceed with the assault. I would recommend using an explosive charge. Use the right door if you want to (#1). Once you've secured this room, approach the hostage. Listen to what the worker has to say to you (#2). As a result, you will have to escort him to a nearby control room. We'll deal with this problem during the third mission of this chapter.
The worker will start running towards a nearby door (#1). Follow him. You will have to wait for him to open the door. After that, this mission will come to an end.