What physiological reaction occurs during the first 1 to 2 minutes of sudden cold water immersion in Chilean coastal waters (typically 10°C–14°C)?

1. Cold Shock Response, characterized by involuntary gasping, hyperventilation, massive heart rate increase, and risk of inhaling water
2. Immediate unconsciousness lasting several hours
3. Instantaneous core freezing of all internal organs
4. Immediate onset of warm euphoria and total muscular relaxation