Kill The Spy

You are playing engineer on 2fort, you are turtleing in the Intel room like vermin.  Another engineer has entered the room, maybe they're here to join you?  You move from your nest to greet him, he runs past you with no hesitation; straight for your nest.  "SPY!" you shout as he rips off his disguise and saps every building in your nest, you sprint to your nest, but it is too late, they explode as you arrive; you spin around to face the spy, he is nowhere to be seen... FIND THAT SPY. KILL THAT SPY.