I spoke to one background extra who had worked on the film RED. The streets were closed off during the shoot and the extras took positions waiting for the assistant director to yell "BACKGROUND!" On cue, the background actors do what they are told, walk, stroll, run, whatever is needed. He mentioned how a random non hired pedestrian somehow managed to wander onto the street of the shoot. A Vietnamese woman on her way home from work who had no clue she had walked onto a movie set.
The group of background actors stopped her and tried to explain that there was a movie being shot and she wasn't supposed to be there. Do to the language issue, she didn't understand why a group of strangers stopped her from walking across the street. Before security could be called in, the A.D. yelled "BACKGROUND!" On that cue everyone ran screaming down the street as blank shots were being fired at racing police cars. A panicked crowd running and screaming including the woman on her way home from work. A half a block down the street the director yelled "CUT!" All of the background actors stopped dead in their tracks to resume positions.
Except for one Vietnamese woman who kept running screaming down the street to escape the gun battle. She probably went home and told the story of a crazy bald guy standing in the streets of New Orleans firing a gun at cops.
Bruce started out as a background actor.