You spot an ambulance approaching with its flashing lights on. What must you do?
You must pull over when an emergency vehicle approaches you with its flashing lights or siren on, no matter which direction the emergency vehicle is traveling in. However, if you're in the middle of an intersection when the emergency vehicle approaches, proceed through the intersection and then pull over immediately. [Right-of-Way, Chapter 3: Driving Safely, Nevada Driver's Handbook]