This action can be used to stop all audio that is currently playing (note that even if audio is flagged as paused it will be stopped with this function and you cannot resume it again later).
The above action block code checks for a mouse button press and if one is detected it then checks a global variable to see if it is not true. If it is not true, then a sound is played and the global variable set to true, otherwise all sound is stopped and the global variable is set to false.