How walker does it

99% sure the thick metal plate stopped the car combined with the scrubbed angular momentum and low speed. Probably put it in nuetral. I base this on a few facts- 1. crown Vic is rear wheel drive. Slamming into park or ebrake would cause an IMMEDIATE locking of the drive wheels. They'd stop turning completely. If they have traction the car will abruptly stop. This is dirt though, so you'd see the rear wheels stop turning and slide on the dirt kicking up dust. 2. At the end you can see the car move forward, then slightly backwards, then forwards slightly. This is consistent with there being no braking force applied, the tire hitting a solid object, rebounding under the vehicle weight, and settling to a gentle stop. The positioning isn't super clear but it looks like the wheel does hit the plate and explains why the plate is there other than to cue the stunt. That's my theory. TL:dr- probably no brakes- nuetral, the metal plate stopped the car.

You wouldn’t have to use full handbrake, just a little handbrake would slow the car without locking the wheels

I'm not thinking they didn't use it at all. Although a standard crown Vic that hasn't been modified has a foot pedal parking brake that makes stunts harder. They may have used it to initiate the slide as I can't tell in the video if it was done using throttle control, weight transfer, or some combination. But the vehicle almost certainly wasn't stopped by the Parkin brake. The behavior at the end is not a smooth stop. It almost definitely rebounds off the plate to come to full stop. Further evidence is that the only visible loss of speed is that of transfer to angular momentum, a closed throttle plate, and the speed scrubbed in the slide- that is the loss is linear and at that speed a slight and constant application of brake alone would likely take longer to stop (hence the plate.) we can also see the vehicle doesn't "squat" as it would from braking. The CV has a long soft suspension and has a lot of body lean. Even police cruisers (we bought and tracked one once for fun.) cont..:.

.... hard ebrake would cause the rear to squat down, throwing it in park or light ebrake would cause some dive. I can see no signs of either. Now- in fairness this car could be modified specifically for stunts. The gearbox or another controller could be modified so that it can stop on its own. That's a possibility. But assuming a standard or lightly modified crown vic without thousands of dollars or advanced fabrication- there is almost 0% chance the transmission was set to anything but neutral or MAYBE drive, and I'd say on the evidence so far maybe 10% optimistically the parking brake was used exclusively to stop the vehicle. All evidence I can see suggests the plate was used to stop it. But I do agree there's a fair chance the parkingbrake was used in the turn, and the turn slowed the vehicle, so we can agree there's at least a real possibility the parkingbrake was used in the overall action.

I just don’t think that’s a metal plate, it’s hard to see but I’d guess it’s foam for him to roll on

I maybe shouldn't say metal plate. It was a guess from the color and fact it has sheen. You might be right. It may be high density foam. It's hard to tell on the phone and from the quality. It seems to move too easily for metal that size but it also doesn't visibly deflect that I can see. So maybe high density foam or a polymer. Also interestingly, what I thought was lag, after pulling this up on my desktop- seems to be behavior of the car. It does NOT carry linear speed as I first thought. It noticeable changes behavior near the end, and it does dive forward and then settle to a squat. A few details I couldn't make out clearly on the phone are more clear on looking on pc. It does seem more possible that ebrake or transmission were used now.