Well, lets see.
I live in an apartment Complex. The apartment complex has security doors everywhere that requier an access card. Now there are 4 security level types:
Tenant: Access to all necessary areas, but not to staff only or restricted
Driver and Maid: Access only to certain areas like basement.
Staff: Access to most places, but limited acces to some Tenant facilities
Security/Manager: All Access.
As you can tell my familly all has Tenant level cards, but ive become friends with the security peeps here, (oddly enough from my mischevious childhood). So anyway, i was given a All Access card (Shhhh, it's a secret. A fun one ^.^)
Well anyway, probably would first of all take one of my mum's scimitars she bought when she was in Turky. My pellet gun, and my Collection of Shurikens and head downstairs to the security office in the basement. ID shut off all of the doors and elevators. Then if i could try to make it that only my card was working.
Id then probably go upstairs and see if that cute Japanese chick who lives on the 17th floor is still un-zombiefied.

If yes WOOT. If not

N yeah i guess id probably look for other survivors along the way... -_-". god they just get in the way
Id try to barricade the stairs by dumping some furniture from the storage room. So that they cant get higher than the 2nd floor.
Id then raid the minimart. Stock up on stuff and bring it all back to my Apartment. Best to be in an area where you know all Entrances/Exits and where shit is. Also, i can raid other peoples appartments looking for food or things that can be used as weapons if needed.
I got access to the roof of the building (30 floors) so i would write some signs up there, probably ligth a fire some kind of indicator im here...
Then id probably sit back and chill, watch TV and if i still got Internet id be on SRF XD