1. The basic Halacha as taught in the Talmud is that ideally the list of all the ten sons of Haman should be read in a single breath, from the words,v’es Parshandasauntilaseres, in order to highlight the fact that they were all executed and hanged simultaneously. The custom, however, is to begin from the wordschameish mei’os ish(“five hundred men”) in the same breath. After the fact, even if he did not read any of it in the same breath, he does fulfill his obligation (Shulchan Aruch and Mishnah Berurah 690).
2. The Reader of the Megillah should ideally not pause between verses for longer than one breath, because he is supposed to read the Megillah like a “letter.” And when he says the words,בלילה ההוא נדדה שנת המלך, “On that night the king’s sleep was disturbed,” he should raise his voice, because that is the point in the story where the miracle began (ibid.).
