I've been the teacher in charge of pairing up Y6 girls for residential bedrooms and it's a nightmare. The boys are usually fine! They honestly don't spend much time in their rooms, it's just to go to sleep and we were super strict about going to sleep/not talking all night. I've spent hours sitting on corridor floors outside bedrooms going "Sssshhhh!" And thinking how if I hadn't volunteered for this I could have been having an evening at home instead of sitting on a corridor floor!
(I did enjoy residentials, just not being woken at 5 on the first morning by noisy children outside my door - after that they get tired and sleep later!)
One year I sorted out in advance who the girls were sharing with. All had happily got into pairs except two. One was a nice sensible girl with no close friend, one was Drama Queen Girl (DQG liked to be the centre of attention, was outraged none of the other girls had picked her first). The girl down to share with DQG was very mature (Sensible Mature Girl = SMG!!) and said it was fine with her. DQG's mother (a professional actress btw) was straight on the phone to me kicking off. She actually said to me "My daughter doesn't want to share with SMG because she thinks she smells!!!" (She did not)
After getting no joy from me, (I was polite enough not to say "No one else wants to share with DQG!") DQG's mother went to the headteacher and, after being told that no, DQG could not have a single room as there weren't any, asked if DQG could sleep on a mattress in the corridor to avoid sharing with SMG. She did not get any sympathy from Head.
After much more kerfuffle we all went on the trip and DQG shared a room with SMG and they were fine. (I kept an eye to make sure DQG was not bitchy to SMG).
DQG did seek attention by having a "sprained ankle" during trip but this magically recovered when she realised she wouldn't be able to go on the zip wire with a "sprained ankle".
Both my DDs did primary residentials. I allowed zero drama about room sharing. OP, please chill out and stop fuelling your child's anxiety and creating drama where there doesn't need to be any.