Below is a summary of selected additional activities in Georgetown district.
1) Mobile Command Centre -D.U.P. base is located in the northern part of district and this is multilevel parking building occupied by enemy soldiers. You can get there in many ways - try to bounce from one of adjacent buildings, fly there, climb up to the top or just start at the ground level and slowly walk up. Use main parking ramps or side staircase to move between levels.
Command centre is located on the top level of the parking and unfortunately it is heavily guarded - you'll encounter here few elite enemies. You can try to lure them one by one to lower levels or attack them from a distance locating yourself on rooftops of nearby buildings. The most impressive way to eliminate them is to use one of most powerful attacks, Orbital Drop for example. Such attacks are very effective because parking is not large and enemies on the top level are standing close to each other.
2) Hidden Camera - The camera you're looking for is located in the place shown on the above screen.
3) Audio Log - You have to get to one of most distant rooftops. Hard disk is located in the place shown on the above screen.