If I have a bank vault that can only be opened by one key, an attacker comes to my house, steals the key, opens the bank vault, and takes everything valuable in

If I have a bank vault that can only be opened by one key, an attacker comes to my house, steals the key, opens the bank vault, and takes everything valuable inside, I think that it would count as stealing in every sense of the word, regardless of the correct behavior of the bank vault in only opening for the right key. I know there's a fun semantic debate about smart contracts hacks, but at the moment this theft does not appear to be in that category.