Some weeks later, Stanley is hosting another poker game. This time, he is winning.
The conversation in this scene is almost entirely small talk. Stella's baby is sleeping in the other room. Stella tells Eunice that Blanche is bathing, and that she'd been told that they made arrangements for her to rest in the country. She's gotten this mixed up in her mind with Shep Huntleigh.
Blanche emerges briefly and asks Stella to lay out her clothes. Stella admits to Eunice that she doesn't know if she did the right thing, but she "couldn't believe her story and go on living with Stanley." Eunice tells her to not ever believe it, and that life must go on.
Blanche comes out. Over at the poker game, Mitch droops at the sound of her voice, and when Stanley chastises Mitch, Blanche starts at the sound of his name. She begins to realize something is going on, but she puts it out of mind as she continues getting dressed for her trip. She talks about how she hopes she dies of eating an unwashed grape and gets buried at sea.
A doctor and a matron appear, in exaggerated institutional garb. Blanche goes to the door, expecting Shep Huntleigh, and is fearful when it isn't him. She backs into the apartment. Mitch won't look at her. The matron follows her in, and approaches sinisterly. The staging becomes less realistic as lurid shadows play on the walls and voices echo against the Varsouviana. Blanche tries to run away but the matron catches her. Stella tries to stop them but Eunice holds her back. Mitch and Stanley fight, and Mitch collapses in sobs.
The matron pinions Blanche's arms and asks the doctor if she should just a straitjacket. The doctor says only if necessary, and then removes his hat, humanizing him. He addresses Blanche directly and politely, and tells the matron to unhand her. Now calmed, Blanche allows the doctor to help her up and lead her outside. Holding on tight, she says "Whoever you are – I have always depended on the kindness of strangers." They exit.
Stella cries her sister's name as she goes. Stanley approaches his wife uncertainly, and she sobs in his arms. The poker game begins again. Curtain.
Almost a coda, this finale is more straightforward than anything in the play. Blanche's artifice has now been entirely stripped away – she is cut down to nothing. The whole cast has gathered to witness her demise, cruelly, a going-away party to which the guest of honor has not been invited. Indeed, Blanche begins the scene off stage, once again in the bath. But now, instead of the cleansing of her own sins that the bath used to symbolize, it has become a desperate attempt to wash off the horror of Stanley's act.
This scene could easily slip into melodrama, but Williams prevents that by writing only functional and mundane dialogue. The scene is packed with small-talk – the real action occurs only in the stage directions. Even Blanche's one speech is mostly meaningless, a bit more of Blanche's poetic babble for everyone to remember her by. The speech is even conscious of its own meaninglessness – she speaks of how she wants to die from eating an unwashed grape, as unheroic and meaningless a death as one can imagine, just a bit more fluff to tide her through to the end.
The famous line in this scene is, of course, "I have always depended on the kindness of strangers." It is an ironic note. Blanche has been forced to depend on strangers - for security, for love, for comfort, for money - because her actual family could not provide. She could not have sex with her husband, so she turned to strangers. She could not support herself, as a single woman in her imaginary Old South mentality, so she turned to strangers. And when in trouble in Laurel, she first turned to her sister - and her sister turned her away. In the end, Blanche is once again sent off from her family, subject to the kindness and the mercy of persons unknown.
The real drama doesn't lie with Blanche or Stanley in this scene – their stories are complete. We have only left to see their logical conclusion. Mitch's reactions provide some fresh context - it is clear that he really did care about Blanche, and he is shamed and hurt by what transpires in this scene. He cannot bring himself to look at her, but he also can't bear to see her hurt.
But what is really of interest in the finale is Stella. She is torn between her husband and her sister, and she is very aware of the decision she has to make. If she believes that Stanley raped Blanche, then she would have to leave Stanley. If she believes that Blanche is crazy, then she has to send Blanche away. Stella seems to know, deep down, that Blanche was telling the truth. But it is finally Stella who is forced to choose magic over realism, shadow over light – desire over cemeteries. She chooses Stanley.
And so Blanche is sent off, half aware of what's happening and half willfully believing in the kindness of strangers, and Stella and Stanley are left to start their life together anew.