I agree, she did, and she’s not supposed to. I think it improved with her last few lines, actually, but the Rani’s thing is she likes to do science, and doesn’t care who gets hurt in the process, but she’s not actually out to manipulate people like the Master.
She’s like if GLaDOS were a time lord.
And fwiw, The Mark of the Rani is one of my favorites in Classic Who. Time and the Rani… well. We’ll always have The Mark of the Rani.