At my school there is a secret trail that cuts through a forest from one of the bad parking lots to campus. Forged years ago by intrepid students, it is extremely dangerous; broken tree limbs and sharp rocks litter the floor, and the tall canopy blocks all light. Should you twist your ankle or fall and hit your head another person may not find you for hours, depending on the time.
Law of the trail dictates that when you emerge on the other side you always look back to see if the person behind you made it out too. If you don’t see the person, just keep going, they’re gone and there is nothing you can do.