If you get caught entering a prohibited area you are likely to get attacked and your relationship with that faction will deteriorate. Sneak and crouch when you enter forbidden zones and quietly assassinate guards that are in your way as you search for alternate passageways that will help you reach your destination unseen. The Lockpicking talent is useful for this, though it isn't the only way to unlock new paths. A point or two in Science not only gives you the ability to craft potions and ammunition, but also lets you blow up certain walls with explosive alchemical phials.