The Smoke Detector part 2

I beat the smoke detector!  I called my landlord after fighting with it some more last night.  He called me back and apparently there is a pin in the side that locks it in place so it doesn't fall out.  The other one I have clearly doesn't have one of these.  Well I got it down and took the battery out and shut up the beeping.  My landlord said he would come and replace the battery today.  He hasn't so far but so long as the beeping stopped I don't really care.  Not really sure why I need 2 smoke detectors right next to each other anyway.  Oh well.  The beeping stopped so I am happy.