Mrs. Mallard briefly grieves with her sister, and then retires to be alone. This would not have been questionable then or today, people often feel the need to grieve and composes themselves alone.... in private. The window does not encroach on her privacy, it's simply open when she enters the room. She doesn't open the window.... she merely sits in a chair nearby, and the action outside of the window reminds her that life goes on. The sounds and smells of the world outside awaken something in her, and at first, she's somewhat frightened.... until she realizes that the world outside is now hers, that as a widow she is free to move about and act in ways that hitherto had not been possible.