I thought flandre's room is in the basement, assuming this is her room.

Hakase64 said:

I thought flandre's room is in the basement, assuming this is her room.

I would assume this is post EOSD where she has graduated the basement but is still under house-arrest. In my head cannon, she'll eventually be let out on occasion to eventually bump into a suitor to control her, and naturally evolve into a morrigan-style beauty and Do your best Kogasa-cham will probably play out.