Riding Shotgun

Speaking of pressure: Back at the apartment complex, a police negotiator is shouting at the third-floor window, trying to talk down the man with the rifle and knife. I'm still manning my station behind the pickup truck — although for a few seconds I consider barging into the building waving my Entertainment Weekly press pass to demand that the crazed gunman tell me what movies he rented on video last week. A heavily armed SWAT team arrives and fans out around the building. I decide to stay put.

''This guy could start blasting at any minute,'' van Munster says cheerfully, ducking behind my truck to reload his camera. ''The first week we started filming Cops, some guy took a pot-shot at me. It's a nauseating feeling having someone shoot at you, I can tell you.'' Then he darts back closer to the gunman's window, into what the police charmingly describe as the area's ''kill zone.''

According to the so-called Hawthorne effect, the act of observing is supposed to affect whatever is being observed. Certainly there is no overt sign of reality-meddling while I'm there-no producers, say, slipping suspects $50 and telling them to run for it. ''We don't stage anything,'' insists van Munster. ''Never. If I catch a cameraman setting up a shot, he won't work on this show again.''

But there does seem to be something of a reverse-Hawthorne in the air: The observers are clearly affected by the observed. Earlier in the evening, Officer George drove Cops to another apartment complex in Vegas, where a 46-year-old woman had been found dead in her car — possibly a suicide. ''This stuff can really get depressing,'' the sound engineer mumbles, watching the coroner examine the body. Van Munster nods. ''A few years ago, we videotaped a very bad drowning,'' he says. ''I just lost it. I was walking back into my hotel lobby and I just started crying like a baby.''

My ordeal behind the pickup truck finally ends after about 40 minutes, when the Vegas fuzz coax the gunman into custody. ''Get that camera out of my face!'' he sneers at the Cops crew as he's wedged into the backseat of a squad car. Shirtless, heavily tattooed, with a fashionable skinhead 'do, he looks a bit like the guy with the banjo in Deliverance. Nobody from Cops is anxious to approach him with a TV release form.

''Well, I doubt we'll be using anything from tonight, anyway,'' Langley says later. ''We weren't close enough. Sometimes what you get on tape just isn't dramatic enough.''

Easy for him to say. Next time I'm bringing my own bullet-proof vest.