One of the important things for you to know in order to be able to defend against a Sarin Gas attack is what exactly it does to the human body so that you can see the effects on others and, hopefully, have time to protect yourself. Sarin does not directly kill, rather it turns a person's nervous system against them.
Unique in it's potency but not necessarily in it's mechanism, Sarin is a cholinesterase inhibitor. In other words, it disrupts the neurotransmitters which our nerves use to talk to each other. They actually do worse things than disrupt the communication, they change it in a manner that tells the nerves to do things that they would not normally do. Sarin also destroys the enzyme that limits nerve communication so that any enzyme that gives a nerve an order keeps giving that order over and over when affected by Sarin Gas.
What this looks like in the real world is death by the accumulation of our own neurotransmitters overtelling our muscles what to do. Smooth muscles will go crazy, cramping and flexing over and over, secretions will take sporadic excitement, and excrete wildly, and the eyes water, the nose runs, the mouth vomits and drools, the bowels turn loose and it is a horrible state to be in. Death can come within 1 to 10 minutes.