Video narration
You're working a normal shift when smoke starts sliding down the roadway toward you. The fire is far away, out of sight. Like a seatbelt, the self-rescuer is protection you carry before anything goes wrong—not gear you find afterward. The danger isn't only flames. It's the air. Smoke can contaminate it and overcome you before you walk out. You can stop moving while fresh air is still down the roadway. That is the turn: the self-rescuer is not dead weight. It provides breathable air for the escape, keeping you moving toward fresh air. How long that takes depends on the emergency and conditions. It buys time; it does not let you stay in contaminated air. Once smoke reaches you, there may be no safe time to go back. The self-rescuer has to be on your belt before the smoke comes. Carry it as escape time with you.