What term refers to a sudden disruption in a situation that requires that a person develop new methods to deal with it?

Was giving by lincoln on march 4, 1865-as lincoln prepared to speak, the civil war was drawing to a close-lincolns address of 703 words was the second shortest inaugural address-lincoln mentions god 14 times-505 of the words were one syllable -he used the word "war" or it's pronoun 9 times