When a driver is trapped inside a crushed commercial vehicle cab with heavy structural steel compressing their lower limbs for over 1 hour ('crush syndrome' / 挤压综合征 risk), what first aid precaution is vital during extrication?

1. Rapidly notify professional emergency medical rescue (120) for IV hydration before releasing the entrapment, as sudden release of crushed limbs can flood the heart with lethal potassium and toxins
2. Immediately pull the trapped limb with a heavy tow chain connected to another truck
3. Administer large amounts of sleeping pills to the driver before extrication
4. Apply tight tourniquets to all four limbs and submerge the patient in hot water