When a passenger bus breaks down on an expressway and cannot be moved, what is the mandatory protocol for handling and evacuating passengers?

1. Turn on hazard flashers, place the warning triangle at 150m+, immediately evacuate all passengers out of the bus and over the right-side crash barrier onto the safe grassy verge, and dial 122/12122 (车靠边、人撤离、即报警)
2. Keep all passengers seated inside the bus with doors closed while waiting for a tow truck
3. Let passengers walk freely along the left passing lane of the expressway
4. Instruct passengers to push the heavy bus along the expressway shoulder