If we assume that the inside is a person sleeping on bed in a house, which is Room. I guess that there was no difference between house and room in 3000+ years ago because it was too difficult for ancient people to build a big house with many rooms. So a room is a place for people to sleep.
However, it is possible that ancient people traveled or moved with arrows because they had chanced to meet wild animals, or enemies. When they reached the destination, they put down their arrows with the arrow heads down on the ground or floor. If it has a roof, there should be a house or room for rest.
Both explanations are reasonable.
The bronze script of character Room is
The top is the roof, and the bottom is the character To. We see the bottom of To is like an ax. In Post 244, I discussed the character King （王, see Post 244) , the bronze script of character King is
So the character To (至) may be a weapon, i.e. arrow. I am not sure.
The small seal script of character Room
The song typeface of the character us
室Its pinyin is Shi4.