In Firefly, we are introduced to the Reavers; humans who were claimed to have reached the edge of space and went mad from seeing the endlessness of it all. Causing their entire mental state to degrade into primal rage and fury that haunts the entire galaxy of the Firefly Universe.
However, we find out in Serenity they were the 0.1% of the population of Miranda that acted conversely to the Pax gas agent, causing them to go insane.
My question then comes back to, how did they keep the mental status to be able to pilot starships and go on raiding parties instead of tearing each other apart? What is it about being a Reaver that makes them immune to each other's rage?