“but you can tell it is on as you can hear the sound in the background.”
Huh? I never hear any sounds, only once in a while the strong hiss from the speakers and only in the period when the tablet was still new. But I agree that there seems to be a lot alive backdoors, when you THINK it is off, it is still alive.
Always after killing Android to go to W10 I have to wait a very long time or keep pressing the on/off button a long time before it eventually decides to show something to me. But not while going from W10 to Android. For that reason I use a shortcut that kills W10 very effectively. But switching from Android to W10 is a pain in the ass. I press the on/off button and I press off, and it reboots. Never ever is it really going off (from Android) so I can boot W10 with ease! Why?