Quick video to demonstrate what a safety bearing is. A safety bearing is a direction of travel that will lead you to a road, railway which can lead you to safety when lost in the woods or when your GPS fails.
Before leaving for a hike, look at a map of the area and figure out what is the nearest road and determine the bearing. If anything happens while on the trail, you can opt to use the safety bearing and bushwhack to safety.
It’s like being in a big city like Montreal or New York. No matter where you are in the downtown, if you ever got lost, you know that by going in a certain direction you will eventually hit a major street where you can get back on track.