Kastor stood by the stairs and listened to the chatter on the police band cut off.  Floor by floor it just cut out.  In an analog system there would have been static, but it just cut to eerie silence in a staccato rhythm as whatever was happening hit floor after floor.  The disarming didn’t go as planned, apparently.  He swore and patched in.
“This is Petrosky on Floor 75.  Change of plans.  This is now an evacuation.  Get the whole building cleared out, on the double.”  He opened the door to the cubicle farm and hoped there was enough time.