If a heavy truck rollover becomes physically inevitable during an accident, what self-protection posture should the driver adopt inside the cab?

1. Ensure seatbelt is fastened, grip the steering wheel firmly, press back against the seat, brace legs against the floorboard, and tuck chin to chest to protect the head/neck from roof crush
2. Unbuckle the seatbelt and attempt to dive headfirst out of the side window
3. Stand up in the cab and jump toward the passenger seat
4. Release all controls and extend arms straight toward the windshield