quote:
Sure, as long as you're just looking around, they don't bother you, but the instant you try to pull something, you'll have three dead drones, and a thousand invulnerable ones coming down on you like a ton of bricks 
Well yeah, that is true
if the survival of the operative is important. If not, then all he/they have to do is set up their bomb(s) and such and detonate them. Voyager has proven that the Borg will allow you to set up bombs throughout their ship with no interference. Or, you could genetically engineer someone to produce a virus that kills borg really quickly and then let them get assimilated. Or, just teach a drone to be an individual and then give him back to the collective and he'll cause a huge uproar, leading to 1000s of drones becoming self-aware and leaving the collective, all to become the personal army of a Soong-type Android's evil brother. The Borg are probably the worst designed race in any semi-reasonable Sci-Fi universe.