Once you have removed a site editors permission to edit & delete a page it will still show on the admin/content page of the site, and that can be useful for users to see the site structure.
Other times it can be confusing, and often causes at least a momentary thought glitch for the user before they go on to edit whatever it is they logged in for.
You can remove the node from the content listing page altogether if the current user doesn't have permission to perform any operations on it.
Just drop the following into your module and you're good to go.