She has compassion.

[Maybe not the first word that anyone would ever use in reference to Nisha, but if you were to dissociate her tendencies from Jack's, that's where the difference would lie.]

I saw the shape she was in after Rota burned down. I could tell Jack wasn't helping her recover. So...

[He shrugs.]

...of course I'm not going to hand her over. Can't leave her like that after all she's done for me...all those opportunities to become stronger.