What will happen?
The radio and Axon's outputs will both TRY to drive the wire. Just will cause bad things to happen and the servo won't know what to do. This could damage the output of either the radio or the Axon.
This will not work!
You can have either the radio or the Axon drive the servo signal but not both at the same time.
If you want the Axon to take over control there are a couple of ways to do this.
1- Run the radio's outputs into Axon inputs and have the code output these to the servo. Then when the Axon takes over it stops outputting from the radio and outputs its own pulse train.
2- Use external logic, AND gates, to select either the radio or Axon outputs to go to the servo.