Hmmm. I would say that enjoying it would be 'sadistic.' I haven't seen evidence for or against Wanda being sadistic. However, I would say that causing hurt (physical and emotional) with a detached efficiency and no apparent sympathy for the suffering she is causing is cruel.
Basically, I am viewing cruel as 'Causing hurt without remorse' whereas sadism is 'Causing hurt for personal pleasure,' if you can see the distinction? Perhaps if I said 'Remorseless' rather than 'Cruel', it would have been clearer to others what I mean.