If a car dies while in operation and the interior battery light turns on, this is typically a result of the battery dying completely. In other cases, the battery light may turn on as an indicator that it is not recharging like it normally does.
If the car continues to run after the battery light first comes on, then the car is running off the stored energy of the battery. The owner should replace the battery as soon as possible. If the car has completely died or the area seems unsafe, the driver should call to have the car towed to a nearby mechanic or auto shop to replace the battery.