During the episode of ‘Checkmate,’ the doctor-Number 23 reads from a medical report on Number 6 upon whom a series of tests had been carried out by the doctor herself. The result being that Number 6 showed a negative reaction to pain, something which would take super-human will-power. So just how much pain had the doctor put Number 6 through? Earlier in the episode the doctor is quoted in wanting to find Number 6's breaking point. Well if she was conducting physical pain on Number 6, there was her opportunity to do so. When you stop and think about it, Number 6 is put through all manner of conditioning, physical pain, emotional disappointment, and remains unaffected by it all. Number 2 is on record saying that he sometimes thinks Number 6 isn't human, I think he's right. And yet when it does come to physical pain, by the time of ‘Hammer Into anvil’ when Number 2 puts the point of his shooting stick sword to 6’s forehead, he appears to have lost the ability of having a negative reaction to it!
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