Automatically set to reverse gear (R) in the case of mountain rollers (N)

What happens then? I’m afraid that this will happen to me by mistake at some point. I drive every day on the way to work, among other things, a 3km long mountain stretch, where I can just roll the car ( V70 Built. 06 ), without having to give gas or slow down. At the bottom I turn on ( D ) again. What would happen if I accidentally am in mind ( or still very tired) and push forward ( R ), instead of back to pull ( D) ?? Is that somehow locked, or does the gear fly around my ears? I hate to try it (whether conscious, or by mistake). Greetings, Andreas