Noise

Noise is low sounds that can be heard by guards at close range. The range is about 5 meters in game. Noise doesn't go through walls.

Guard Reactions
When a guard is in idle or search state, he will face to the noise source to check it for a short period of time until seeing anything suspicious. A guard will NOT turn on radio on hearing noise.

Noise of Guards
Guards' footsteps can be heard in the fog of war. Players can hear noise of guards through walls.