You do know that, you can just
walk over and pick up the key and then go read the newspaper, at any point in the chapter, you don't have to start over. Unless you saved yourself into a corner, but I don't remember if that was possible.
Does that mean you got the ending where
Naomi get's her tongue cut out?If so I would consider you lucky.
But yes, the game will try to do this to you on purpose,
you will have to be aware of it. Multiple save slots are encouraged.
The official Oni of the Shin Megami Tensei IV board