1. Robbers can just enter the palace ??
2. The emperor got only ONE house ?? (I used "house" as suggested by you, not palace)
3. The emperor needs to escape when there is a robbery ?? You mean he has no guard or soldier to take care of his safety ?? He has to run for his life ??
Seriously and honestly, I am 200% sure you can rewrite the history of ancient China if you are able to provide clue on (1), (2) and (3)
Btw, the last time I checked the the size of The Forbidden City covers an area of about 72 hectares (180 acres) with a total floor space of approximately 150,000 square meters (1,600,000 square feet). It consists of more than 90 palaces, 980 buildings and over 8,728 rooms.