They’re both basically impulse-driven, even if in Dru’s case the impulses can be triggered or augmented by psychic knowledge, so what they ‘wanted to do’ could be absolutely anything.

I actually saw a story that spoke of the crew having just dealt with an unlikely Dru-and-Harm team-up, and that it had actually been a bigger problem than any of them would have expected. I can’t remember what that story was, though.