Source: Colombiana (2011), an American movie. A prison bus arrives at a police precinct. There's only one prisoner in it. He's in handcuffs and wears a sack over his head. Before he steps off the bus, the US marshal that escorts him says: Alright, big step. Down you come. Could you tell me please what big step means here? Does he tell him to take a big step (a movement made by putting one foot in front of the other) or does he mean "beware of the big step in front of you" (step = a support for the foot in ascending or descending)?