Now you will have to take out a second ADA unit. It's very important because it scrambles the radio signal. As a result, you won't be able to use the drone inside the scrambled zone. DON'T go there just yet. A large group of enemy soldiers will arrive near the entrance (#1). You will have to make a surprise attack. Kill all enemy soldiers. Once they're gone, head on to the main area of the park. The second group will be located on your right. Use the drone to help you locate them (#2). Position yourself correctly and take them out from a safe distance.
Start moving towards the central area of the park. You've got to be very careful. There are some new enemies on your left (#1). Just as before, it would be best to kill them from a large distance. Make sure that the area is clear before you move on any further. You should be able to reach the scrambled zone very soon (#2). Don't worry, the ADA unit is very easy to find. Sadly, you won't be able to use the drone here.
Like I've said before, you shouldn't have any problems locating the ADA unit, especially since it's in a very obvious place (#1). Additionally, its lights were turned on. The main problem is that the area is swarming with enemy troops. It would be best to find a good shooting spot. Start aiming at the enemy soldiers (#2). You will have to secure the whole area around the ADA unit. Thankfully, you can still use the tactical map. It's best to zoom in the view. You should be able to spot a few additional units.
There's one soldier that you've probably overlooked. He's patrolling the area by the two large buildings (#1). You MUST kill him right now. Proceed to your objective. You should encounter a few additional units along the way (#2). Make sure everyone's dead.
Get closer to the ADA unit. You have to make sure that no one's here. Head on to the highlighted spot. It's located on the left side of the vehicle (#1). Place the charge and move back to a safe distance. Now you will only have to wait for the ADA unit to explode (#2). CHECKPOINT 3.