I found the inside cabin very creepy. Considering 20 cruises under my belt over a dozen years, it was a cabin we called the BAT CAVE.
There were 3 of us with 4 beds upper/lower and one upper always had our extra clothes piled on it. The cabin was very large for an inside (350ft2) but not having a window/porthole just left us feeling like "what time is it?" even with a clock on the dressing table.
You're right--there's only one way to know...