Bitcoin is virtual, no needs of a bunker to stock them.
Bitcoins are in the blockchain and everybody can have a copy of this blockchain.
To access of this bitcoin, only a private key is needed.
I was wondering too that I almost started doubting everything I have come to believe that bitcoin is virtual that there actually be a physical coin to it where people like who Op is portraying are hiding their stash away from the public eye.
But again I don't know how much this people who have that would made them build as large as this bunker because if they could, I wonder how large the bunker of Satoshi would be if the report on the internet is anything to go by about his purported stashing of about 1 million bitcoins. This is not only misleading but could cast doubt over the believe of newbies bitcoin without even reading the article.