Esther

So today I decided to read Esther again. I've read it so many times and heard the story more times than I can count, but somehow I still couldn't resist reading all the way through to the end of the book.

We talk alot (in the church) about how Esther was a normal girl and then she suddenly became queen and saved the Jews. We don't really talk alot about how she failed to tell the king.

Esther was beyond scared she was terrified of what she had to do. If someone was to come before the king without being summoned, they would be put to death! She was the queen, but the king still had to call for her. In this point of the story, after the decree against the Jews was sent out and Mordecai came unto Esther and asked her to intercede for the Jews, the king had not called for her in 30 days. A whole month, It had been a whole month since the king had called her!

So, as you probably know, after a bit of back and forth between Esther and Mordacai, Esther was convinced to go and speak to the king. She requested that Mordacai go back and ask the other Jews to fast for sake for three days and she and her maidens would fast as well. And so, on the third day, Esther put on her royal clothes and went to see the king.
She was not killed obviously, and invited the king and Haman to a banquet, where she planned to tell the king of her heritage. The king did not know that Esther was Jewish, because Mordacai had warned Esther not to say anything

At this first banquet however, Esther did not speak about the Jews and/or the decree against them. The Bible doesn't say exactly why (that I can find anyway), but most people take it to mean that Esther was frightened.  She may have been, it seems like a sound assumption. I really wonder the exact reasons she waited.

She told him the next day at a second banquet.  The king was very angry when he was told and ordered Haman be hanged on the very gallows that Haman had built to hang Mordecai from. The king's decree against the Jews could not be reversed, but the king sent out another decree allowing the Jews to arm and defend themselves against any who attacked them.

When the appointed time came there was much fighting and the Jews killed five hundred men and Haman's ten sons in Shushan. How many had the others killed in the rest of the provinces?
This always sort of bothered me. I don't really know how to reconcile killing others, even in self defense, with the command not to kill in Exodus 20:13.  If anyone has an answer for this, please let me know. I'd love to hear it.