EMP = either your safe is locked down forever .... or until you hire someone to drill it.
I remember once, years (wow, decades) ago when I was an intern, there was a safe in a government building that everyone forgot the combo to and for which no one could find any master list. This was a safe designed to store highly classified documents, mind you.
I watched as a guy with a crow bar and a 5 lbs dead blow busted it open inside of 5 minutes.
While it gave me a new perspective on the phrase "safe cracking," it also made me feel a lot less secure about putting anything in a safe...
...though hopefully, I'd hear someone smashing their way into my safe and be able to do something about it before they finish...