You are a vampire looking to become a member of the Vampiric Council. They meet somewhere in this mall. Find their offices, fill out an application form. You will end up needing to do something that impresses them (e.g. save their lives, kill a werewolf, show up in a mirror, defeat a vampire killer, etc) before they will accept you. They will inform you what they want.
Do be careful around Mirrors and Sunlight. Probably best to avoid wooden stakes too.
1. Fill out an application form to become a member of the vampiric council
2. Become a member of the vampiric council
3. Survive to the end
As alluded to in thread, some players are exiting the mall by train once done. You are not required to buy a train ticket and cannot leave the game. Once you are on the vampiric council, you must survive until the end.