She is 'racing against the clock' to be sure the assignment is handed in on time.
Her mind was 'racing'. [=she had many thoughts going quickly through her mind]
Researchers are 'racing (against time)' to find a cure.
(..) ...could be running out of the door of Bag End. He should just slam the door behind him. Don't have him be too fussy, you know? He's really kind of racing-- And he's got the contract in his hand. Comes bounding out through the gate and racing down this path. We're supposed to be doing (..)2012 The Hobbit: An Unexpected Journey