Whether the rape has happened or not, she does believe that Raja has raped her as shown on more than one occasion. She believes that this guy has raped her and to add insult to the injury, he has mentally and physically tortured her.
Therefore I can't judge her harshly for this act, is it right? No but it's understandable. Who wouldn't do the same thing in her position. To be honest it's not like she will not save him tomorrow, she is only delaying to help him and not refusing to help him.
Before you call her inhumane, remember this is the same guy who she believes to have raped her and refused her, her justice by kidnapping her grandmother so that she had to take her case back. If this wasn't the protagonist, you would haven't made this post, just because he's the hero doesnt mean he isn't a monster.
I have my problems with JM but this isn't one of them. If anything, this was a human reaction from her. He is a monster to her, he has kidnapped, tortured, 'raped' her so why wouldnt she even think about letting him die for atleast for one second?