Good Golly that's a weapons room!!!
That's someone with a ludicrous amount of money to spend. But you ain't kidding about finding it! He'd likely never give it up, but just imagine some unfortunate occurence happening....a heart attack, for example, and then house sits empty. Someone checks it out after fire demolishes nearly the entire hourse, but the basement/weapons cache is untouched. The stragglers see the sealed door, bust it open and WAAAAHOOOOO!!! Jackpot!