Kill switch only stopping one motor

I'm using a flipsky dual 4.20 to drive 2 flipsky 6354 motors.

I'm new to brushless control, but I think I've got the settings mostly how I want them.  One thing that intrigued me was the killswitch option.

When I activate the killswitch (whichever option I choose; I can manage with any of them) it only kills one motor (local to the killswitch).

Is there a way to communicate that killswitch to both sides via CAN?  It seems like it should kill everything, but it does not.

I'm using ADC1 throttle with reverse button.  Am I religated to switching both sides of the ESC thru ADC2?  AFAIK (but I'm probably wrong) there is only one PPM

Thanks for the help.