What is the mandatory immediate sequence of actions that a driver and escort must execute if a hazardous chemical transport truck experiences a breakdown or minor leak on an expressway?

1. Steer the vehicle onto the emergency shoulder (应急车道), turn on hazard warning flashers, shut off the engine and master power switch, set up reflective warning triangles ≥ 150m behind the vehicle, evacuate upwind, and call emergency services
2. Stop in the middle overtaking lane, leave the engine running, and inspect the leak with an open flame lighter
3. Continue driving at high speed until the cargo tank is completely drained onto the road surface
4. Immediately disconnect the trailer and walk away without notifying any authorities