Ground Control C02:
The Defecter
In this mission, Biship Delendre of The Order is trying to defect to your side. This is the first indication that there is a religious aspect to your enemy. Note again that you can set each mission's difficulty separately if you get stuck, although I played through all at Normal from the start to write these walkthroughs.
You get 2 sets of infantry in this mission - in my mission it was the Screamers and Eagle Claws, but the names vary randomly from game to game. You should load up the infantry and move to the first contact point, but don't worry about running too quickly - he's going to die anyway. Something that annoys me greatly, but such is life. Stop and fight whoever gets in your way, then move up to him.
He says that 'Project Garm' has devils involved, and gives you a data disc before dying. Note that in-mission dialogue can't be skipped past - sort of annoying sometimes. When you're done with him, head back south again to the pickup point. You have to be in the APC to be picked up.
Your character starts drinking at this point because she's so depressed about her job. Can't you have a cheerful reason to fight??
Ground Control Walkthrough