I believe the story was that the taxi driver was in the strip club where Mangum worked receiving a lap dance from her when she excused herself and (apparently dressed again) marched off to the parking lot and drove off with the taxi.
The driver and a security guard tried to stop her and, when they couldn’t, they called police which led to the high speed chase.
Later, when the cops had stopped the taxi at a place with no exit and began to leave the squad car to arrest her, she spun the car around and drove off, nearly running over one of the officers.
Hope that helps.
Ah... okay...
So she stole the taxi from a man “to whom she was giving a lap dance”, but not while she was actually giving the lap dance.
Much clearer now.