What could love, the unsolved mystery, count for in face of this possession of self-assertion which she suddenly recognized as the strongest impulse of her being! (15)
Can love really just be cast aside like this? Here, Mrs. Mallard reduces it to the "unsolved mystery" and presses on, casting aside her feelings for her husband and however many years they've been married for this freeing idea of "self-assertion." It's hard to say if she's crazy with grief, if she's in denial, or if it's possible to be unhappy in a purely regular marriage. You know, like Don and Betty Draper in Mad Men.
She was beginning to recognize this thing that was approaching to possess her, and she was striving to beat it back with her will – as powerless as her two white slender hands would have been.
When she abandoned herself a little whispered word escaped her slightly parted lips. She said it over and over under her breath: "free, free, free!" (10-11)
Weirdly, the concept of freedom seems to take over Mrs. Mallard's body. She's "powerless" to stop the feeling of freedom from "possess[ing] her," even though the idea of freedom traditionally seems to indicate choice and personal authority. Here in order to be free, Mrs. Mallard can't be free from her idea of freedom.
Some one was opening the front door with a latchkey. (21)
Even though people are inside the house, it's still securely locked. In order to enter, one has to be admitted or possess a key. So, even in a time of extreme emotional feeling or loss, propriety is observed, things remain orderly, and the doors stay locked. In addition, we can tell immediately that whoever's entering in this sentence is someone who belongs or has the authority to be there, since he (in this case) has a key.
There would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow-creature. A kind intention or a cruel intention made the act seem no less a crime as she looked upon it in that brief moment of illumination. (14)
Mrs. Mallard's "illumination" does away with context and motivation. Now all that matters to her is that she can achieve freedom. Past ties and expectations, stripped of "a kind intention or a cruel intention" are revealed as shackles that have been tying her down. Even the love of a good person keeps one from being free.
Into this [armchair] she sank, pressed down by a physical exhaustion that haunted her body and seemed to reach into her soul. (4)
Mrs. Mallard's "exhaustion" almost seems to squish her. In addition to deliberately confining herself to a single room in her house, now it seems like her tiredness is confining her body and "press[ing] down" on her soul. She can't escape from this tiredness or run from it, just like she can't escape from the bad news about her husband.
When the storm of grief had spent itself she went away to her room alone. She would have no one follow her. (3)
Mrs. Mallard willingly confines herself. In order to achieve the physical and mental state she desires. She wants to be by herself, so she deliberately shuts herself away in her room. Instead of going out into the world and losing herself in a crowd, she tries to hold her body and mind within just one room.
Her fancy was running riot along those days ahead of her. Spring days, and summer days, and all sorts of days that would be her own. (19)
The "days ahead" that will belong just to Mrs. Mallard seem almost too many to count. It's as if she can't even hold in all the glory and the goodness of those days, stretching out, days where she can do whatever she wants.
"Louise, open the door! I beg, open the door – you will make yourself ill. What are you doing Louise? For heaven's sake open the door." (17)
Even though Mrs. Mallard is finding freedom behind the closed door, Josephine doesn't understand it. Instead, Josephine is worried Mrs. Mallard will "make [her]self ill." The confined space seems dangerous from the outside. Perhaps, though, if Josephine knew what Mrs. Mallard was really thinking, she'd be even more convinced about the danger of being alone.