CURRENT STATE
If a character is in a DARK room, and they look into a NOT-DARK room, they CANNOT see the NOT-DARK room.
The opposite is also true.
If a character is in a NOT-DARK room, and they look into a DARK ROOM, they CAN see the DARK ROOM.
DESIRE STATED
Character in DARK room CAN see into NOT-DARK room.
Character in NOT-DARK room CANNOT see into DARK room.
EXAMPLE
It is night time. You are outside a house. The lights are on inside. You can see into the house perfectly. The people inside the house cannot easily see out of the house, unless they press their faces up against the window.
Another example is a one-way mirror, like in an interrogation room. The lights in the room are on. The lights behind the mirror are off. That way, the observers cannot be seen by the person in the room.
If the lights in the observation room are turned on, the people in that room are visible to the person in the interrogation room.
Now granted, this mostly has to do with the way glass works and how reflect it is or is not. Still though, it doesn't make any sense based on how reality works that a person CANNOT see into a lighted space.