How we cite our quotes: All quotations are from Die Hard.
Quote #1
MCCLANE: It's okay, I'm a cop. Trust me. I've been doing this for eleven years.
One of McClane's first lines in the movie tells us his occupation. And a few minutes later, we learn he's NYPD. As his later conversation with Argyle suggests, McClane's very loyal to the force.
Quote #2
MCCLANE: Why the f*** didn't you stop 'em, John? 'Cause then you'd be dead, too, asshole. Think, goddamn it! Think!
Poor McClane's torn between his desire to help out Takagi and his need to survive. If he had stepped in to save Takagi, he'd likely be dead himself. Or, at the very least, he'd be a hostage—and then they'd all be nowhere. But still, it can't have felt very dutiful to sit back and watch his wife's boss get blown away.
Quote #3
ELLIS: Cops?
HOLLY: John.
ELLIS: John? Aw, Christ. He can f*** this whole thing up. What does he think he's doing?
HOLLY: His job.
ELLIS: Bulls***. His job is 3,000 miles away.
Ah, but a cop is never really off duty, is he Ellis? Sure, John McClane may be NYPD, but he's more than just a jurisdiction.