Everyone has their musts when looking for an apartment. I like a high floor and natural light. A friend refuses to live without a dishwasher. Bill Rigdon’s clients need a walk-in closet that can withstand nuclear fallout. “I’ve never been busier,” says Rigdon, who has been building panic rooms for 40 years and is seeing a surge in demand in New York right now. The city’s ultrarich are feeling anxious, and they are soothing themselves with electrified door handles and bulletproof windows. Curbed’s Bridget Read talked to the builders (and brokers) behind these luxury fortresses, who are about as paranoid as their well-resourced customers. “I don’t trust the bodyguards. I don’t trust security,” one told her. “I don’t trust anybody.”\xa0\xa0