Normally, a character's actions can be heard by anyone in the vicinity, subject to the level of background noise. A character can attempt to move or make actions quietly, so that others around him/her are unlikely to hear the movement or action.
To do this, the character makes a dice roll using his/her Stealth (including Move quietly specialism) + CO. There is a modifier to the dice roll based on the type of action that the character is trying to make. For example, if a character is moving very slowly and carefully (i.e. half normal speed), he/she gets a +2 modifier to the dice roll; if he/she is walking normally, there is a +0 modifier to the dice roll; if he/she is running, there is a -3 modifier to the dice roll. In addition, a character who is wearing metallic armour has a -3 penalty on the dice roll.
To hear someone moving quietly, a character must make a dice roll using his/her Tactics (including Hear sneaking specialism) + PE, and get a dice roll result that is greater than or equal to that achieved by the sneaking character. There is a penalty on the hearing dice roll for extensive background noise or distractions of between -1 and -6 depending on the extent of noise and distractions.
New dice rolls must be made for every minute of activity.