The ANBU had been too easy. The one in front of the door was out before he knew what hit him, a very clean severing in the spinal cord. In fact, it was bloodless. The second nearly died of fright, until Kabuto literally stopped his heart's blood flow. That would have killed him in a neat three minutes, but Kabuto didn't have that kind of time, so he also stopped blood flow to the brain. The third wasn't as neat. Scrambling up the man's nervous signals gave him the time though to make neat incisions through the man's mask and give him a new face, though.