I have been wondering about these 3 expressions of "in case of".
In case of emergency
In case of an emergency
In the case of an emergency
I figured that the first one simply means to say "in any case of emergency" while the second can´t stand on its own. Something should follow, right? Though I don´t know why. Is it because it is more closely defined by the indefinite article? The third one seems to mean "in regard to" and something specific must follow? Is any of this correct?