Unless you've left something out, I feel like you're being unfair to the instructor here by assuming malice for giving oral exams. Have you voiced this concern with her? My reaction is that this instructor is putting enormously more effort into her students than she's being paid to, I'm not sure you realize how much more of a time investment that is.

I've had students come to me about test anxiety and if I trust that they have a decent understanding then I'll offer an option to test orally instead. A lot of students do much better with oral exams. It allows me to say okay, you can't answer this particular question, but I can probe adjacent things to give partial credit. I can see you do have some understanding of what the question is meant to test for, I realize that this specific detail is tripping you up and you would do fine with a question that didn't involve that one hiccup. With a written exam, I'm just grading on how well you answer the one question. It's not reasonable to take stabs at how much better you might do with a slightly different question, because that would be massively influenced by the biases of what I'm expecting out of you before the exam starts - it's hard for that not to end up at better grades for students I like more. I can't look beyond how well the steps you've written on the paper lead towards answering the question you were given.

In a better world I would offer them for everyone, but it's a massive time investment. I'm reluctant to make that offer unless I already have some confidence they're decent with the material, because if I give an oral exam and they're struggling it might be hard for me to not leak frustration with having two hours of my time burned for no benefit, and if they read that on me it won't help with test anxiety and won't be better for anyone.

Seriously, just start a dialogue with her about this in private.