Although laws of illegal use of holy items may not be relevant to this room, the Rabbis established extra protection for the Holy of Holies: Pesachim 26a
[Not] Having reminders of our sins in the Holy of Holies: Rosh HaShanah 26a
The measure of this room, somehow, didn't include the space taken up by the Ark: Megillah 10b
The dimensions of this room: Megillah 10b