It's
ironic if a
fire station burns down while everyone's out fighting a fire elsewhere because the fire station is for housing people to put out fires and therefore is the least likely place for a fire.
It's ironic to use words so that they mean the opposite of their literal meaning. (
Sarcasm and such)
Incongruity between the expected/normal results and the actual results.
(Request permission to nuke Webster_1913, sir!)