I first spot Jake Gyllenhaal in the lobby of the InterContinental Hotel in Toronto, wearing a button-down shirt and sunglasses. I am supposed to be interviewing him in 20 minutes about his role in “Nightcrawler,” an enthralling new genre flick about a psychotic freelance cameramen who films crime scenes for local news programs. These freelancers, or nightcrawlers— unscrupulous vampires of the night— listen to police scanners for crashes and other headline-worthy crimes, then speed to the scene and film what they can. The resulting footage gets sold to local outlets for cash. The general rule of thumb: the bloodier the scene, the bigger the payout.