snap into action

Translations
внезапно начать действовать
As soon as the alarm rang, the firefighters snapped into action.
Как только зазвенел сигнал тревоги, пожарные внезапно начали действовать.
Definitions
To begin doing something quickly and energetically, often in response to a situation that requires immediate attention.
Words
action

noun
действие
snap

verb
щелкать