I would think if a person had a car bomb they wouldn’t draw attention to themselves the way she did.
If the car had been laden with explosives she most likely would have rammed the barricades or one of the patrol cars at the White House to set it off. Using non lethal force to disable her isn’t going to make a bomb any less likely to detonate. Maybe someone not directly involved in the chase make these decisions, since they can keep a cooler head and be more objective.