@Legion-114All power must run through the main power lines, if they manage to cut that almost all power would be cut off. The only remaining power would be pretty much right next to the source.
...... Why? None of the vampires use viruses. And neither does the blood. That would just sit there, doing nothing.
Gabriel can anticipate defence systems, and manipulate his way past them. And they have enough brute force to break their way through pretty much anything. They could further employ Bedivere, Chantelle and Victor again to port in and out of the base, Guerilla warfare style, and deal as much damage as possible.
Hive is probably awesomely lethal. But unless they get help from Dawn or the Purge, they're pretty screwed here. I've been planning this one out for a while now, although it'll be interesting to see how HIVE chooses to defend itself.