The Buffer is only there to stop the car safely if it passes the lower landing at the designed speed (plus the tolerance of the safety governor) it does nothing for falls from height that is the job of the safety brakes. In fact in most lifts the danger is the car 'falling upwards' out of control because the counterweight is heavier than the car plus passengers. Lots of people have been killed in this scenario, there was a bad accident in Canada. The EU changed the European Lift regulations probably 20 years ago to require 'lift cars to be fitted with a parachute to prevent falling upwards' or that is how the English translation of the French original ended up. However the requirement was not retrospective so lots of lifts in high buildings are not fitted. Not sure what the situation is outside Europe.