I also do not owe them any rent, or break anything also (since i live alone there, never brought any stranger here and barely cook also).
Since my country do not have these kind of property, but i think i should be called a subdivided unit (bec it looks like they divided the whole floor into 4 private room)
Move out before your contract ends makes you look like you are running and have something to hide. It doesn't matter whether the landlord has gone to the police or not. You should report it and that would also protect you if anything was to disappear from the flat. You can also report that concern and take pictures in case it happens. Putting your own lock would also solve the problem.
Hmm if it is subdivided as it seems to be, I doubt the landlord is going to chase you re the unfinished contract. I also doubt he'll give your deposit back. If they truly believe you stole from your neighbour they might chase you re that though and if the police did eventually speak to you it wouldn't help your story.
Seriously if it were me I would be proactive and go to the police rather than waiting for them to question me
You can hire a locksmith to get the lock changed.