Not unusual for people to not hold themselves responsible for despicable things if they feel they were acting under orders from another. In fact people actually tend to do that even if they would never dream of it on their own.
Harmony in all likelihood would probably have found that moment as a rather convenient moment for Paalm to get shot and have Wax leave, but he supposedly didn't physically take over her, or so he claims.
So he also claims, Paalm passed on to the beyond actually asking Harmony to take care of Wax on the way out, so it would seem if Harmony is honest (no proof to the contrary) she actually doesn't really mind nearly as much as she seemed when she was driven mad. She was also much more coherent while short a spike than ReLuur was, so . . . I don't really trust that spike of hers.