What is the right course of action now?

Your answer is correct because in the event of an accident inside a tunnel, safety rules focus on preventing further danger to people and traffic. Leaving the ignition key or transponder behind when leaving the vehicle allows emergency responders or authorities to move your vehicle if necessary, which is a standard safety measure. Exiting the tunnel via the designated emergency exit is important to ensure your personal safety and to avoid blocking the tunnel any further. Waiting inside the vehicle is generally not recommended because tunnels can be hazardous in case of fire or smoke, and quick evacuation through emergency exits is preferred. Understanding these rules helps you respond safely and properly if involved in or near an accident in a tunnel.