CELERITY [\suh-LAIR-uh-tee\] , noun:
1.Rapidity of motion or action; quickness; swiftness.
My Sentence:
If only the authorities took the warning about a secular threat seriously and acted a decision calmly at the same time with celerity, thousands of lives would have been spared from nuclear catastrophe.
Origin:
Celerity is from Latin celeritas, from celer, "swift." It is related to accelerate.
Source: Online Dictionary