Far Cry 3 Blood Dragon Classic Edition

This is story related. You can't miss it. I found it was easiest to climb up the right side of the Garrison and deactivate the shields, and let the Blood Dragon take care of the bad guys.

(Copied from version Xbox360 - JTJDG666 Solution)

Story related. Unmissable. Very early on into the game after you sneak past the Blood Dragons, you will come across the first Garrison.

You can either stealth your way through it and pick off the enemies or throw a cyber heart into the base and watch the Blood Dragon unleash chaos. Have fun.