When the police encounter a locked door and can’t kick it open, they just shoot the doorknob and push their way inside. At least that’s what happens in the movies, anyway. For us ordinary, non-law-enforcement citizens, getting a locked door open is pretty boring because we just use a key (or risk getting arrested.)
That said, these Bang Bang Doorknobs by Nikita Kovalev are really something else. Basically, these doorknobs are based on the look of 9mm Makarov pistols. To open the door, just pull the trigger and open.
I don’t know you’re supposed to lock your doors with these doorknobs though, as I don’t see any slots for keys or anything else. Maybe it has something to do with cocking the gun, or maybe these are strictly for interior doors which don’t lock.