Thankfully, you will be able to take out several rebel units on your own (#1). You will have to scope the zoom feature in order to score decent headshots. Once they're gone, head on to the extraction zone (#2). The rest of the team should be following your lead.
I would recommend that you reach the extraction zone by moving near the northern buildings. I had to deal with a single opponent here (#1), so it wasn't a huge problem to kill him. Once he's gone, you would have to go to the north-east. Be careful, though. One of the enemy snipers may still be hiding to your south (#2). You would have to secure that area as well.
Remember that you won't be allowed to make any unnecessary stops, however you will have to make sure that none of your squad members got lost along the way. Head on to an allied gunship (#1). Obviously you will have to take a seat inside the helicopter and wait for the rest of the team to join you (#2). Once the gunship is in the air, this mission will come to an end.