For me, there is no single way that particularly turns me on. I like to consider the way she would act given some situation. When I'm writing, I typically expect the doomed slave to be dazed, unable to grasp the reality that she is about to be nailed to a cross to die. She might gradually come to the realization that this is really happening to her.
But if she's been in a prison cell for a few days before, she knows she's probably condemned already, and she expects the sentence I hand down. She's listless, convinced she's going to be crucified and there is no escape.
If she's a Christian, she might believe she is dying for a worthy purpose. She accepts her sentence stoically, knowing she is going to her reward.
If she is a rebel, she might also accept her sentence stoically, believing she is dying for the revolution. It's when she sees the rest of the rebels and their leader also going to be crucified that her whole world changes and she knows her death will have no meaning at all. Then it becomes a frantic struggle to escape what is coming, begging not to die, etc.
I really like the stories from history like that of the slaves of Pedanius Secundus who were all crucified because one slave murdered their master. Then there were the 40-50 slaves of the associate of Sextus Pompeius, son of Pompei the Great. While they were in Sicily, Pompeius learned that his associate was looking to make a deal with Octavian to surrender. Pompeius murdered him, blamed it on the slaves, then crucified them all. So there were all of those slaves who were dragged out of bed, unaware their master had been murdered, to be taken out and crucified still wondering what had happened. Pick just one of them, a young woman, and imagine how she might react.
There are so many ways to write it.
