The first two-thirds of Collateral is leisurely enough to allow you to consider the little things—such as why the hell Tom Cruise’s head is a Brillo pad of grandma gray. And why the outfit he’s wearing as Vincent, “badass sociopath”—a shirt to match his gleaming teeth, a suit the color of his regrettable ’do—is nearly identical to the one he wore as Charlie, Kmart-hating Rain Man–keeper. These probably aren’t the details one should be distracted by in a gritty crime drama by Heat director Michael Mann, but there just isn’t a whole lot to Collateral’s story about a contract killer and an unlucky Los Angeles cab driver to keep you occupied. Written by Pirates of the Caribbean “screen story” contributor Stuart Beattie rather than by the auteur himself, Collateral contains hints of Mann’s lyricism but none of his depth. The focus is on the cabbie, Max (Jamie Foxx), who tells his fares that the job is temporary as he saves money to start a limo service. The businesslike Vincent gets in his taxi and pulls out a bunch of benjamins to convince Max to be his chauffeur for the night; shortly after Max agrees, a body lands on his windshield. Much of the film consists simply of the two men driving around the city and talking about their deal—which Max naturally wants to break—with occasional interruptions to kill some folks. Meanwhile, Vincent’s conversation is laced with carpe diem sentiments as he accuses Max, who’s been at this “temporary” gig for 12 years, of being the type of always-dreaming, never-acting sheep who’s “hypnotized by daytime TV.” Mann’s digital camera nicely captures the electric seediness of L.A. in the wee hours, but Beattie’s script doesn’t let you in on who Vincent is or why he’s pursuing this evening of homicide—which translates to zero momentum as the movie wears on. Both Cruise, as heartless killing machine, and Foxx, as nerdly, hyperventilating clock-puncher, are entertaining in these departure roles, but the philosophical stuff isn’t enough to hold your interest in two characters who are merely broad sketches. Though the action does eventually kick into a higher gear—this is, after all, “A Michael Mann Film”—waiting for something to happen might just make your hair go gray.