That’s a tough safe. Most can be opened with a can opener.
I am a big proponent of safe storage.
Liberty Centurion is a strong safe. Inch and a half or two inch thick pins all around IIRC. If you can’t get locking mechanism to release, you will probably have to destroy the safe to open it.
Did it not come with a backup key? If it did and the key has been lost, you might try writing to Liberty Safe to request a replacement.