To specifically address that issue...
You should store as much water as you possible can, and have a method of filtering bad water for drinking:
Make provisions for heating, or, rather, staying warm, given your expressed concerns. I'm thinking clothes, blankets, and one of these:
Note that this device is safe for interior use as it has a low-oxygen shutoff.
The four immediate-need basic groups you must have:
You already have shelter, and, due to the nature of your building, probably will have in most circumstances. It would be prudent, however, to have a 72 hour pack ready to go near your exit...because, you know, shit happens.
Finally, you might want to consider talking with your neighbors (if you like them
) in some fashion to discuss in a friendly way how "the building" will deal with things if you all aren't as lucky in the future.
Have a plan... --
The most powerful weapon in the world is ignorance. Politicians exploit it to achieve almost anything they want.