Whats already being done:
You can currently kite Springvale to the courtyard preventing the spawn of ADDITIONAL adds
Whats different about this thread:
As a mage, I was kiting Springvale to the courtyard and my nitro boost fizzled, so naturally I used mirror image to hold them in place while I ran to the courtyard. The difference is, after I used mirror image, only Springvale came out to the courtyard, and the guard as well as the officer add despawned. This gave the group an easy achivement where as before you had to interupt and kill those 2 adds to begin with then proceed to kill Springvale, and even then the adds gave buff to springvale.