If a bus catches fire inside an Austrian motorway tunnel and cannot be driven out, what safety procedure must the driver follow under ASFINAG tunnel safety rules?

1. Lock all doors, remain inside the bus with passengers, and wait for emergency services
2. Engage reverse gear and attempt to back out of the tunnel against traffic flow
3. Attempt to extinguish an engulfed engine fire using passenger drinking bottles
4. Stop on the right shoulder, switch off engine, leave ignition keys in the vehicle, immediately evacuate all passengers, and guide them along illuminated escape signs to the nearest cross-passage/emergency exit