I didn't notice the alarm either, I didn't even know anything had happened at all until I left this morning. I actually spoke to the landlord who said that if we had gone out in the hall we would have been able to hear the alarms, and that there are 2 separate alarm systems, a building one and one for each apartment, which could explain why many of us slept through it. Still worrisome though.

I'm glad no one was hurt and I think I'm also kind of glad I didn't wake up to a fire alarm since cat-wrangling and panic would have ensued.