extra info:
when driving at high speed and needs to stop drastically(*this is also used to avoid accidents, like cars that stop suddenly, or bikes that "die fire" suddenly)
-imagine you are speeding at 120km/h, 5th gear
-step on clutch and shift to 4th gear, release clutch, step on brake pedal
-next 2 seconds, step on clutch and shift to 3rd gear, release clutch, step on brake pedal again.
-repeat til 2nd gear, and your car has most probably slowed down drastically to around 20km/h ~ 40km/h, depending on your timing and skill.