The final scene depicts Laura as "she blows the candle out." What does this act represent and what message is it sending?

In the final
scene of "", Tom'ssyncronizes directorily with Laura blowing out the candles of the
candelabra.  It was the candelabra that Amanda had given Jim (the gentleman caller) to take and
go talk to Laura who felt sick and left the room when she discovered that the gentleman caller
was the boy she had a crush on in high school.

Tom leaves the house forever
after he is berated by Amanda for bringing home a gentleman caller for Laura who (unbeknownst to
Tom) was already engaged.  Tom leaves St. Louis and "descended the steps of this fire
escape for the last time and followed from then on, in my father's footsteps, attempting to find
in motion what was lost in space. . .Perhaps it was a familiar bit of music.  Perhaps it was
only a piece of transparent glass. . .  (referring to Laura's glass menagerie). Perhaps I am
walking along a street at night, in some strange city, before I have found companions.  I pass
the lighted window of a shop where perfume is sold.  The window is filled with pieces of colored
glass, tiny transparnet bottles in delicate colors, like bits of a shattered rainbow. Then all
at once my sister touches my shoulder.  I turn around and look into her eyes.  Oh, Laura, Laura,
I tried to leave you behind me, but I am more faithful than I intended to be!  I reach for a
cigarette, I cross the street, I run into the movies or a bar, I buy a drink, I speak to the
nearest stranger--anything that can blow your candles out!  (The following passage synchronizes
with Laura blowing out the candles) . . . For nowadays the world is lit by lightning!  Blow out
your candles, Laura---and so goodbye. . . "  (She blows the candles out.) 

Tom is troubled by how he deserted Laura.  He tried to help her and his mother, but he
could not live with them any longer--the guilt is overwhelming and he finds no peace.  He wants
the interminable reminder of what he has done to end. . .  and thus asks Laura to forgive him
and to forget about him.  This is the symbolism in the passage of asking her to blow out the
candles.  Laura and Amanda are destined to continue living their lives with little income and no
husband to take care of Laura.  Tom is asking her forgiveness and she grants his request by
blowing out the candles.

Note:  In real life, ' sister's bedroom was next to
an alley where she could hear cats fighting and screaming at night as she went to sleep.  So
Tennessee painted her room white and brought home little pieces of colored glass for her to
collect in order to brighten her room as well as her spirits.