Which of course will need a button to be disabled as well..
So now we have a vault with a complex combination, Which can be opened by turning it on it's side. Now we are going to add a second layer to the security, so we are adding a padlock. To make sure the padlock and the safe can be opened in case of emergency, we add as a security feature that the padlock when held upside down will open with the combination/key. All of this will need another security......etc, etc.
The best way to secure a microsoft windows based system, is by leaving the power switched OFF.
On that note the only way to secure any system at all is by leaving it powered off in a vault and throwing away the key, so no one can steal the hardware.