I've been noticing that while the other cabal inner guards will attack an enemy who is standing there but not fighting, usually because they were rescued, the Destructor doesn't. Buggy? Watched some very long raids where the healer was rescued in the first round, and the destructor didn't bring him back into the fight, ever.

Mucho Thanko!

As far as I know, the inner will only try to attack people if it's not fighting. I'm guessing in your example the Destructor was fighting someone else while the healer healed them.