Charles Ellicott Commentary Esther 9:6

"And in Shushan the palace the Jews slew and destroyed five hundred men." — Esther 9:6 (ASV)

The palace. —Doubtless the whole royal city, rather than the palace strictly so called. It is obvious that even Xerxes would hardly have allowed bloodshed, other than by his direct orders, within the precincts of the palace.