In the minute and a half clip titled "Good deed accomplished!" the motorcyclist can bee seen rushing to reach the SUV's back bumper. Once he gets there, he skillfully grabs the cup, and begins chasing the car while waving the mug at the driver.
After noticing the biking hero, the SUV driver slows down and rolls down the window for the man to give her the cup.
"My daughter!!" the owner yells before emptying the cup on the pavement.
The biker then goes his own way and eventually does a "mission accomplished" dance with his hands at the 1:27 mark.