You just have to spend 2 of your BTC to build your own bunker 
Discussion
What if my country enter in war and my bunker is requisitioned for civilians or a military shelter 🤔
Thats a good objection....maybe na mente is less dangerous....or multisig, that is definitely more rational...because digging a long tunnel in Tibet, Nepal or out of any militar jurisdiction is a bit expensive
Talking seriously, your question is a really good question that all good bitcoiner should try to answer ...