You should remove location leak too, like this :
Creat a variable point (for example PointPop)
Set PointPop = Center of Region 009
Here do whatever you need on this point (special effect & creating boss)
Then set a custom script : call RemoveLocation(udg_PointPop)
And Bribe is true, you should Destroy the special effect, and not to destroy the sound (it makes sometimes the game crash).