Wouldn't it make more sense to call the two options "They work slowly..." and "They react with..."? I don't think the options have to be "positive". You are going to pick the outcome you prefer among the possibilities anyway. I think removing the negatives would make it much easier to understand, I myself was a bit confused at first. Also for someone unfamiliar with PbtA it might not be obvious than choosing one implies that the other one happens, so to speak.
Also, what happens on 2-6? You get both? Something else?