Made threat a subsystem instead of dynamic-attached.

code/__DEFINES/subsystems.dm

@@ -152,6 +152,7 @@
 // If the subsystem isn't listed here it's either DEFAULT or PROCESS (if it's a processing subsystem child)
 
 #define FIRE_PRIORITY_VORE			5
+#define FIRE_PRIORITY_ACTIVITY		10
 #define FIRE_PRIORITY_IDLE_NPC		10
 #define FIRE_PRIORITY_SERVER_MAINT	10
 #define FIRE_PRIORITY_RESEARCH		10