The fear system dictates how scared a given NPC is. There are three levels of fear; normal, scared and "Crack-up". When an NPC enters "Crack-up" mode, Blake has only a limited amount of time to reduce their fear level, or the NPC will kill themselves, attack Blake and other NPCs, attack the environment, or die of a heart attack. Each NPC responds differently to different surroundings; for example, medics tend to scare easier than soldiers. Generally, however, fear increases when entering rooms covered in blood, entering dark locations, finding particularly disfigured corpses, being attacked by multiple enemies, and hearing enemies but not being able to see them. When an NPC is scared, it affects their performance; soldiers become less accurate, engineers take longer to repair fuse boxes and medics don't heal characters as quickly. Blake can reduce fear by giving NPCs adrenaline, topping up their ammo, moving away from particular locations, or successfully defeating enemies.