Observe the "Important safety notes" section.

BAS operates in emergency braking situations. If you depress the brake pedal quickly, BAS automatically boosts the braking force, thus shortening the stopping distance.

Keep the brake pedal firmly depressed until the emergency braking situation is over.
ABS prevents the wheels from locking.

The brakes will function as usual once you release the brake pedal. BAS is deactivated.

WARNING
If the BAS malfunctions, the brake system still functions, but without the additional brake boost available that the BAS would normally provide in an emergency braking maneuver.
Therefore, the braking distance may increase.