4) Destroy the Bridge
Now you will have to go back with the ENTIRE team (order them to follow your lead) to the main encampment (#1). The base should be safe, however more enemy units are heading your way. Head on to a nearby bridge. It's going to be located in front of you. Now you will have a few seconds to prepare for a counter-attack. I would recommend ordering two of your men to hide behind cover (#2).
The third team member may use a nearby heavy machine gun. You would have to select him from the menu. Aim at the machine gun and choose Use function (#1). This won't be necessary, however it would help you in your defence. Hide behind one of the sandbags and wait for the enemy units to arrive in this area (#2). Rebel soldiers will appear near the bridge.
Once you've dealt with the first group, reinforcements should arrive near the bridge (#1). You won't have to destroy the helicopter, because it won't fire any missiles at you. Instead, take care of all of the remaining enemy troops. You could also order your sniper to move left (#2).
If you've decided to move the sniper, he will have a much better view at what's going on in this area (#1). As a result, he will be able to take out all remaining soldiers. Once they're gone, head on to the secured bridge (#2). The rest of the squad should be following your lead. You could also activate the tactical map to make sure that the area is clear.
You will have to reach the opposite end of the bridge. Once you're there, order your men to make a stop. They won't have to follow you. Just make sure that they've crossed the bridge. Turn left. There should be a narrow passageway here (#1). Go there now. Once you've reached your destination, press the X key. You won't have to detonate the charge, because this will happen automatically. A new cut-scene is going to be displayed on your screen (#2). This is it for this mission. You will be debriefed very soon.