If it makes you feel any better, I don't think you're trolling. One approach here would for your teacher to talk about how you deal with this. Another approach, and apparently the one your teacher uses, is to continue to insist that you both learn whatever script you are enacting. You don't need everything in muscle-memory do something after your partner doesn't do what you thought she was going to do. While I agree with your understanding of improvisation as it is commonly used, you only need to learn to "improvise" one or two steps, or even a simple pause, or weight change in place. Those are things you already have in muscle memory.