You'll gain the Power Throw and Aftertouch abilities in this chapter, thus allowing you to start working towards the Hardball, Finesse, and Aftertouch abilities as you play. You'll also encounter the shield guards in this chapter, who can do quite a bit of damage if they close enough to melee. Just use a power throw on their shields and shoot them with your pistol to kill them, and keep a safe distance.
(The video belongs to BonersGames)
(FYI i used
http://www.xbox360achievements.org/game/dark-sector/guide/credit belongs to wickeddark)