As above, we just got a device with an internal lock, hoping for less sound, whilenin public. Our concern is with the lock as it's not a simple twist of the key to unlock. It's kind of fidgety and don't think it would be useable in an emergency, and/or may permalock or key snap. The device is Master series Rikers 24/7. We have not worn this yet and are back in the CB 6000 after viewing the lock. Any advice on lock maintenance or prep for this device? Or do we just stay away and find another device with an external lock?