Your Phone Dies in 20 Seconds

You have finished a late shift at 12am. The streets of the small town have been emcompassed in darkness. The buses have terminated services for the night and you have no choice but to walk home, which is 25 minutes away. You hear the sounds of footsteps behind you. You have a strong feeling in your gut that you are being followed. Hands shaking, you pull out your phone. You only have 5% battery left on your phone. You haven't got much time.