Why on earth do you allow someone who has no clue what they are doing put an ecollar on your dog?
Sampson is probably in a defensive mode because he doesn't understand Ax's motives. Things need to be clear to a dog...
I would practice NILIF
and have Ax completely ignore Sampson.
Don't use the collar again..... Ax should be trained on how to properly use it. Get a trainer for help in this.