Devon asked the receptionist about Naomi's room number, they even gave him the number of her room as he told her they were classmates.
The receptionist was aware of the whole Academy staying in the hotel. But Devon was not satisfied, he asked for Ryan's room number.
...
"Why is Mitsuda's room on a different floor and on a different block?" Brandon muttered to himself.
They were walking through the hallway to their rooms [Or so he thought] Devon's intention from the start was to see and talk with Naomi before sleeping.