the floor. but now notice another man in the blue shirt. that s dwayne bullard, a b.a.r.t. service worker. i seep him about to punch her. i had no choice but to react. reporter: the b.a.r.t. station in san francisco was crowded on may 10 when this video was shot. while bullard got involved, others kept their distance. they reacted by pulling their phones out and filming it. that s it. that s the only assistance i could get. reporter: i asked him what was going through his mind at that moment of truth, when he confronted the naked crazed man in defense of that woman. i m thinking of my mom and my sister and my wife, and any of the ladies in my church. it could have been anybody i know. i would want somebody to do the same for my family. so i just did what i should be doing. helping. reporter: this video has been seen by the b.a.r.t. police chief. obviously we don t expect him nor do we want him to engage with anybody who is involved in criminal activity. but he h