In the absence of foreign antigens, a juiced-up immune system sometimes can't stop attacking its own body.

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If you can stop the virus reproducing in someone's body, you not only save his life, you also reduce the number of viruses for him to pass on.

ECONOMIST: Thirty years of a disease

Also, as UK policemen are trained to 'shoot to stop' by aiming at the trunk of the body - this can result in innocent people being killed.

BBC: Less than lethal: Shooting to live

Nerve agents stop the body from breaking down the acetylcholine neurotransmitter, overwhelming the nervous system and causing convulsions that can lead to death within minutes of exposure.

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