If a passenger coach suffers an unavoidable mechanical breakdown inside a long expressway tunnel, what is the driver's primary emergency protocol?

1. Steer the bus into an emergency parking bay (紧急停车带) if possible, activate hazard flashers, place the warning triangle at least 150m behind, evacuate passengers to the tunnel pedestrian cross-passage/sidewalk, and use the tunnel SOS emergency phone
2. Leave the bus in the middle lane, lock all doors with passengers inside, and walk to the tunnel exit to flag down help
3. Instruct passengers to push the bus through the tunnel in neutral gear
4. Turn off all vehicle lights to avoid draining the battery and wait for highway patrol