As fast as their legs can carry them - Idioms by The Free Dictionary
as fast as (one's) legs can carry (one) (redirected from as fast as their legs can carry them)
as fast as (one's) legs can carry (one)
As fast as one can run away. You need to get away from here as fast as your legs can carry you—it's too dangerous!
as fast as your legs can ˈcarry you as quickly as you can: When he heard the police sirens, he ran off as fast as his legs could carry him.