In explantion of this and i like it cause it works in an RP sense too - it's their coding that kills them:

The 255's show up to kill you for not having access to the area, since the truce ended we shouldn't have access to any of them.

That being said, they show up to kill the target who hasn't tagged, and realize that you have tagged - the logic and counter-logic of those things produces a contradiction - this then causes their head to exploded - becuase they need to kill the authorized unauthorized person.

It's a lot like the old school star trek with Mud and his clones, or the futurama episode with santa-claus - the evil robot not the jolly old fat man.

If you don't know what im talking about with the last two references don't worry about it, if you do:

Too bad these agents don't have contradiction proof software.

hehe "everything i say is a lie, i'm lying" - good times. 

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Proof of this btw, is that the 255 won't die if you've not tagged the access node. 

~Darminian