If Hydie took Quinn over, things would get complex. If it wasn't a mutual decision where the two of them can still exist and have a better understanding, something tells me things would go south fast. Hydie is still a monster and without something tempering her, she will probably end up succumbing to what she obsesses with until she loses her mind and becomes nothing more than a monster that can be controlled. The best scenario for a Hyde isn't one to overwhelm or eliminate the other but for both to find peace with one another, and thus final oneness.