Board Thread:Speculation House/@comment-27951513-20160310231729/@comment-25936766-20160727131354

Maybe the trigger is like the inverse of Myrtenaster's. While Myrtenaster's activates the Dust to channel it into the weapon, here the trigger would activate a "safe mode", to prevent it from firing sonic waves.

Either that or it is like Myrtenaster and it activates the Dust.