Fetching details from the dictionary...
same room
sharing a room; occupying the same room
同室の患者と仲良くなった。
I became friends with my roommate in the hospital.
大学の寮で、彼と同室になった。
I was assigned to the same room as him in the university dormitory.
会社の研修で、見知らぬ人との同室は避けたい。
For the company training, I'd like to avoid sharing a room with a stranger.