a missing "y"

[alan gould]

i saw this sentence:

"Le quartier devient invivable. La police ne se déplace même plus."  

i would think it needs to say "...ne s'y de'place..." to refer back to le quartier.  maybe it's optional -- it means the police don't move from where they are, but the "y" isn't necessary cuz it doesn't say where they would move to if they did move.  

[Chantal Savignat]

It means "La police ne se déplace même plus dans ce quartier quand quelqu'un l'appelle"

As "Le quartier" is already clarify in the first sentence, it's not useful to refer back to "le quartier". It's possible but if not it's still right.