The 40-foot-wide, two-story property is crisscrossed with video cameras and motion detectors, but should a threat become serious, Mr. Wilzig, his wife Karen, and two children can retreat to the master bedroom, behind a door that weighs 1,488 pounds. Not that visitors could tell, since it pivots as smoothly as any door in the home.

“The only way you would know is if you left your finger in the jamb,” said Mr. Wilzig, who helped sell the bank in 2004. “Then you would know.”

A peephole offers a 180-degree view of the hallway outside, a critical feature, Mr. Wilzig said: “It can be just as important to know when it’s safe outside to be safe inside.”

Inside the master bedroom, everything seems normal. The windows look like the typical two-pane variety, and they are, except for a transparent bulletproof polymer, which at the time was cutting edge. (Now, similar technology can be found in scratch resistant cellphone screen covers.) Kevlar and steel are just behind the drywall.