I also like the idea of cutting off a trooper’s connection to his Geist as a breach effect. The core book spends so much time emphasizing how interconnected people are with their Geists that it’s not outside the realm of possibility that a trooper wouldn’t be able to function without it.
Wait, my Geist is down? How do I know friend from foe? How do I know how many bullets are left in my clip? Who am I going to get tactical information from? Who is going to manage my connection to the other troopers in my squad? What if I get new orders? AHHH! I better just leave!
Good idea. - And taking a trooper out could be that the hacker “turned the Geist against him”, as in producing sensory overload in the quantronic aura, while asking whether to delete the last few thousand date entries in the personal calender one after the other, while commanding Comm quality equipment to a “regular annual general update shutdown”, etc.