Circumvention of Parental Control

Hi, 

I subscribed to Norton 360 a day ago and installed the Parental Control application on my (11 yr old) son's windows 10 computer. We tried together out its functions and it took him exactly 5 minutes to circumvent the "device lock" function, which brought him to the "login" screen of his computer. He simply logged in and in the time, before parental control would log him out again, he created a new wordpad document on his desktop and initiated a shutdown of the computer. This shutdown terminates all processes running in the background including parental control, but then the shutdown is stopped with a message "wordpad is preventing the shutdown, to you want to abort, wait, force". He then aborts the shutdown and can then use his PC unrestricted. 

Is there a possibility to prevent the parental control process from being terminated, or prevent the execution of other apps during PC lock? 

Regards, Mathias