Hi.
1) It's a strange decision to start the camera when the screen is off using the volume buttons, especially since the camera turns off if the screen is off the screen.
2) "Volume button
This trigger is triggered when the volume buttons on the device are pressed. In most cases, the trigger only works when the screen is turned on, volume tracking works with the screen turned off if the device is in wake mode (for example, when playing music). you can choose whether to allow the volume to be updated or to keep the previous volume when the buttons are pressed. it is recommended to use this action with restrictions, since constant interference with the operation of the volume buttons is undesirable."