The only way someone can fall out of their room is if they can crawl through the porthole.
The only way someone can fall out of their room is if they can crawl through the porthole.
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Actually, you can't fall out the porthole -- on the ships I've been on, the "porthole" (most newer ships now have real windows) is sealed shut. Now, if you have a room with a balcony, it's possible to fall overboard. And certainly, there are other locations on the ship (besides her room) where she could have fallen.
Uh, a lot of cruise ship cabins have balconies, and in the version I read, her brother last saw her on her rooms balcony.