If you drive manual geared car, just step on the clutch and brake safely, when the car stopped safely turn off the engine.

If you drive automatic geared car, switch the gear stick to N Neutral and brake, when the car stopped safely turn off the engine.

Even if above wouldn’t “work” for some reason, a cars braking system is tremendously over-dimensioned to be able to brake a car even when the engine is at full throttle, just step on the brake and slow down the car as fast as possible, and don’t be afraid something can get broken by braking hard, a car is designed to handle these kind of forces, it is that simple!

Remember, don’t prolong the braking for several minutes as the brake disks will get overheated and braking capability will reduce.