Extremely fast leak spanning break, I think

• As fast as possible

Wiktionary Word definitions in Wiktionary
a. (context music English) Extremely fast, the fastest possible tempo. (from 18th c.) adv. (context chiefly music English) Very quickly. (from 19th c.)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Prestissimo \Pres*tis"si*mo\, adv. [It., superl. of presto.] (Mus.) Very quickly; with great rapidity.

WordNet Word definitions in WordNet
adj. (of tempo) as fast as possible adv. extremely fast; as fast as possible; "this passage should be played prestissimo"