It’s all a calculus of necessity and threat. A soldier’s brain shifts into a survival mode where the instinct to stay alive overrides most other drives. That instinct is amplified by a tight social contract—if you don’t do your part, everyone’s on your shoulders. Then there’s the mental payoff of purpose; if the mission feels meaningful, the brain releases dopamine, making the fight feel worthwhile. When the smoke clears, the lack of external stimulus forces the brain to look for a new trigger—often the memory of what was lost or the pressure to not let comrades down. It’s a loop of fear, duty, and a search for meaning that keeps the cycle alive.