Straight ahead is the ornate Gate of the White Eunuchs, which leads into the Third Court, and the private quarters of the palace.
Only white Eunuchs could pass through the Gate of the White Eunuchs.  
mnli hypothesis: Only white Eunuchs could pass through the Gate of the White Eunuchs.   premise: Straight ahead is the ornate Gate of the White Eunuchs, which leads into the Third Court, and the private quarters of the palace.