Strife alarm

From DoomWiki.org

The alarms in Strife are simply a notice for enemies. They are normally activated after the player fires a non-stealth weapon, which is any weapon besides the fist and the poison arrows. The alarm will sometimes start due to an alarm trigger (often a green doorframe, or going through a yellow doorframe without a uniform). Wherever an alarm goes off, nearby Acolytes and Templars are alerted to the player's presence and attack, while shopkeepers shut their shops. Robotic enemies such as the Stalker and Crusader attack regardless if the alarm is active.