Well, didn't take long to find out what happens when there's a fire. Looks like someone overheated oil in the apartment right below mine. I was about to stay put, thinking it was a false alarm as usual, but someone said they were seeing smoke so we evacuated the building.
The doors did not appear to lock (I'm not sure that they actually can - can't find anything on the door itself except for maybe the weird hinge).
http://www.imagebam.com/image/0466eb29479616
http://www.imagebam.com/image/97c47529479618
Three fire trucks came and they took a long look inside the building. They went outside to peer into the apartment below mine but it looks like whatever smoke someone saw must not have been very much as the big fan they had brought outside remained unused. That fan needed to be used a few years ago when someone at the end of my corridor cooked chicken directly into the oven without placing a pan underneath to gather the grease. The oven caught fire and there was a lot of black smoke. The tissues were blackened when I blew my nose afterwards.
I can still smell some faint burnt/overheated oil though.