Assuming you can try 1 number in 7 seconds for every hour of work you would have 5% chance to open the safe. Unless the number can be changed and owner does it regularly (ideally every day) the number adds up and you can be 100% sure that after 20 hours of work (no necessarily continuous, can be done 1h/day) the safe is compromised (but it's equally possible that it will take less than 10 hours than more). If you think it's a lot of time for some people you didn't see much in this game You could use 6 bots and it could go down to half a night of "work". Why stuff should be easy to crack every time player sleeps?What's worse you can never be sure if someone didn't break you code already and waits for you to put something valuable there (unless you have it in perfectly safe location anyway or change the code often).