Can I suggest you try the two following options:-
1) Press 'OTHER PARTS/TR' button (bottom left of screen). Here ALL or INDIVIDUAL parts can be 'muted' using the buttons immediately below the screen.
2) Go to 'CUSTOMISE' (bottom right of keyboard) Press 'FAVOURITES' scroll down to No.4 (Entertainer) and here you will see the 'MUTE KEYS OFF' function and the 'PANIC'
Either of these two may be what you are looking for.