Hi, I understand what your saying about volume but the reality is if you hold the volume down key whilst the alarm is sounding the alarm only comes on very quiet and then goes silent again over and over again
The second part is I was talking to my wife on the phone when my daughter sent the lost text, I could continue the call as my wife could not hear the alarm, I then pressed the power key and I could use all the functions including turning the phone off, being surprised at this I did indeed switch the phone off, I then called my wife again and this time I kept pressing the volume down key and the power key seperately and the alarm stopped and I had full access to the phone, the only thing I noticed was the phone was now in flight mode, that could have been me pressing the screen I'm not 100% sure.
Hope that helps