Manual override failsafe (with companion computer)

Using the Pixhawk with ArduCopter firmware, a companion computer is mounted on the drone and connected to the telemetry port of the Pixhawk. The companion computer is controlling the drone’s movement using MAVLink ‘RC Override’ messages.

How can I have the option for a human operator take control with a remote no matter what?
Even if the companion computer gets possessed by demons (Sends RC override messages, tries to change flight mods, etc.) the human operator needs to be in control.

You change modes on the rc mode switch and then change it back, quick flip of the mode switch on the rc tx will give you control back. If the companion computer gets possessed and keeps taking control you can keep flipping the mode switch to fight it for control…and then just kill the throttle in stabilized mode and get it to the ground asap