I imagine the following:
EXECUTIVE: The most corrupt cop you've ever seen... I don't know about that line, Tim. I haven't seen the film yet, but there's no way in hell this movie cop―which, mind you, the writers were able to make as corrupt as their imaginations could fathom―is more corrupt than some of the actual cops certain viewers will have seen or encountered in their day-to-day lives.
TIM THE POSTER DESIGNER: I guess you're right.
EXECUTIVE: On the other hand, compared to other on screen cops, who knows? This one might very well take the cake.
TIM THE POSTER DESIGNER: Well, now that you mention it, I'm not sure that's true either. Have you seen Abel Ferrara's Bad Lieutenant?
EXECUTIVE: No, Tim. And neither has Rampart's target audience.
TIM THE POSTER DESIGNER: Heck, even Nicholas Cage's cop character in Herzog's Bad Lieutenant is probably more corrupt than Woody Harrelson's...
EXECUTIVE: You're missing the point, Tim. The exact specifics don't matter a bit. This is not about facts. Hyperbole is a central part of marketing. [Slight pause] Just make sure you qualify that tagline with "on screen."
TIM THE POSTER DESIGNER: But sir, hyperbole...
EXECUTIVE: Hyperbole is one thing, being laughed at is quite another. I mean, have you been following this?
[A few minutes later]
TIM THE POSTER DESIGNER: Wow. On screen it is!