So manyy has many diferent theories about this, but here is what i think.
Seven can't forget about you, and he is the only one in the whole game that knows he is in the game, since he breaks the fourth wall a lot and even says things that happend in the other routes. When you finally end the game, everything is reset, so you need to start again, but he doesnt forget you, that's why he loves you in all the routes. The reason why his and jumin routes are locked is becaues in Jumin's route are hints about this, like seven's call in day 10, and of course seven's route is locked because of all the secrets.
But there is one thing that realllyyyy shocked me, many times on electronic devices things like "errors" appeared, for example "error 101" when something isn't working. I dont know if this is correct but i read on a blog that "error 707" means when something can't be errased, like the memory of a computer....
