Featuring Bill Ryan of the Ryan Investigative Group via the New York Times

An uneventful — by New York City standards, anyway — sunny Sunday in your family sport utility vehicle turns instantly into something out of “Mad Max” when a group of motorcyclists surrounds and overtakes the vehicle, forcing it to stop on a West Side highway.

What do you do? What should you do?

The questions arose after video surfaced on Monday showing an encounter on the Henry Hudson Parkway, in which a family’s Range Rover seems to be stopped by dozens of motorcyclists. The S.U.V. then speeds out of the huddle, running over at least one bike and, in the process, the police said, a biker. The S.U.V., driven by a man with his wife and their 2-year-old daughter, is seen speeding up the highway before getting stuck behind other cars in Washington Heights. By the end of the six-and-a-half-minute video, a biker can be seen shattering the driver’s window with his helmet. The driver was pulled from the vehicle and beaten. The police charged two motorcyclists on Tuesday and were searching for other suspects.

The scene, minus the bloodshed, may not be unfamiliar to New York City drivers, who have encountered similar groups of bikers darting among traffic. What if things go bad?

A sampling of retired law enforcement officers and bodyguards weighed in on what to do if things go bad, acknowledging that there is no standard response.

“This specific situation was definitely one for the books,” David Boehm, chief operating officer of Security USA in Manhattan, said.

He said some of his clients were so rattled by the video that they were calling the office to make sure the company had a plan for similar situations. It more or less does.

Lock the doors, Mr. Boehm said. This sounds like a no-brainer, and yet, that did not happen on Sunday, when the video shows a motorcyclist approach the S.U.V. on foot.

“He actually opened the door,” Mr. Boehm said. “This whole time, the driver never locked his vehicle, or at least his door.”

Another obvious tip: Call 911.

“Try to ascertain where you’re at,” said Manuel Gomez, president of MG Security Services and a former New York police sergeant and Federal Bureau of Investigation agent. “The phone call is only as good as what you give them.”

The 911 call could become important later, after the exhaust fumes have cleared and people are pointing fingers, said Bill Ryan of Ryan Investigative Group. “You’re better off starting the process,” he said. “You want to be the person: ‘Hey, I called the cops. I’m a little concerned this could get a little crazy. They’re all surrounding my car.’ ”

Someone in the car should take pictures of the assailants, or take down license plate numbers, he said. “It gives the police something to start with,” he said.

But after the doors are locked and the conversation with 911 has begun, the time still may come to get out of there.

“Something triggered his flight mechanism, ‘I’ve got to get my family out of here,’ ” Mr. Boehm said of the encounter on Sunday.

If you feel threatened, Mr. Gomez said, “you have the right to defend yourself, by hook or by crook.” The motorcyclists had more than numbers on their side, he said: “Superior weapons, because they were using their helmets. All he’s got is a cellphone and a vehicle. Take them out. Whatever you have to do. Figure it out later.”

A police detective advised: “Don’t get off the highway. Do something to get the attention of the police.”

On the video, the S.U.V. is seen speeding away, only to be overtaken again. Mr. Boehm would have reacted differently. “I would have continued at a very slow speed, even if I’m surrounded,” he said. “A Range Rover versus motorcycles, he’s going to win that battle.”

Ask the 911 operator for help finding the nearest police precinct, Mr. Ryan said. “You’re not running from the law, you’re running to the law,” he said. “Here’s a big one — you don’t want to drive home. If you pull into your driveway, now they know where to find you on another day.”