"Leapt into breach" is a phrase that represents taking swift action in a challenging or risky situation. There are several synonyms that can be used in place of this phrase, such as "rushed in," "charged forward," "took the plunge," "dove headfirst," "plunged into action," "threw oneself in," "sprang into action," "acted without hesitation," and "embarked on a daring venture." All of these phrases represent an individual's willingness to take risks and seize opportunities by acting quickly and decisively. Whether it is in a personal or professional capacity, leaping into the breach is an admirable trait that requires bravery, resilience, and determination.