Is there anyway to get back into dead city once you have made it to subway town?

You can go back to the first disc by returning to the hot air balloon where you entered the area. A man named Charon will bring you back.

I understand that Ive beaten the game on normal and nightmare but the i want to get the cards I missed in dead city but....the door is sealedhttp://steamcommunity.com/id/McBrady/screenshot/558669913711113905?tab=public