The ambient sound is extended to the base itself through such things as hissing pipes, footsteps, and occasional jarringly loud noises from machinery or other sources. Early in the game, during and directly after the event that plunges the base into chaos, the player often hears the sounds of fighting, screaming and dying through their radio transmitter. Quote: Frequent radio transmissions through the player's communications device also add to the atmosphere, by broadcasting certain sounds and messages from non-player characters meant to unsettle the player.