On the island where the lighthouse is for the last mission there are five security measures you need to disable or reprogram.
The first one is the tower in the area at the top of the stairs you start near. You can get up there from the cliffs with some fancy Agility level 2 jumping followed by Blink level 2.
There is an Arc Pylon on the right side that can be taken care of from the red lit area nearby. The panels for two Walls of Light are accessible from a sewer entry near here.
Near the end, in the elevator area, there is an Arc Pylon that you can only take care of by going under the platform it is on and rewiring it.