The work Kab Ha’yashar (listen to audio recording for precise citation) comments that although G-d’s Name is NOT mentioned expressly in Megilat Ester, several verses in the Megila allude to various divine Names through the first or last letters of a series of words (Rasheh Tebot and Sofeh Tebot). It is proper, he writes, to have these allusions in mind while reading the Megila. The Kab Ha’yashar writes that during every holiday, profound sanctity and "new holy worlds" come into existence, and they are revealed in the world only once a year, at that time of the particular holiday. On Purim, this sanctity begins to descend and be revealed at the time of the reading of the Megila. Therefore, one should recite the Beracha over the Megila reading with great awe and reverence, and have in mind when reading the words "Mikra Megila" that this refers to the revelation ("Gliui") of the special lights of sanctity that come to the world on Purim. The congregation should also have this intention while the reader recites the Beracha.
The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in his work Torah Lishmah (195), writes that one should not leave the synagogue during the reading of Megilat Ester, even if he had already fulfilled the Misva in an earlier Minyan. Just as one may not leave the synagogue during the congregational Torah reading, it is similarly improper to leave the synagogue during the reading of Megilat Ester.
