Both matters, your apartment entrance as well as flat entrance. First we should check your flat entrance to check the vastu of your flat and we check the surrounding of your flat, your apartment entrance and other points should be considered.
My advice is to take decision based on the overall plan of your apartment and flat. As per Vastu, if you are buying a secondhand flat, it also matters about the previous owner's life, why are they moving out etc.
If you can post picture of your plan, better advice can be given.