We have brought for our retirment 140 acres,, nice and rural, so that we can be self sufficent , run a few cattle, and hide away if things get bad. It already has a shed on t that has been made into a house, very cozy, but is a shed although it has flushing toilet and power and so on. We are thinking of building something more secure, that we can utilize in the mean time and use as a shelter if needed. We are thinking of using shipping container, lifted a foot of the ground and totally cover with concrete blocks. Would it be fire proof, ie. insulated from the heat by the concrete blocks?cyclone proof?because its so heavy. We are hoping because we are building it off the ground to have a trap door and a tunel off into the bush making an exteral exit. Would it be bullet proof, any ideas and thoughts welcome.