If you have Shell Armor, it is impossible to get hit by a critical hit, lest the Pokemon you are facing be wielding the abilities Mold Breaker, Teravolt or Turboblaze
This goes for Inner Focus as well. Even in haxmons battles, a Pokemon requires the abilities Mold Breaker, Teravolt or Turboblaze to crit or flinch you through Inner focus and Shell Armor
> Shell Armor prevents Pokémon from receiving a critical hit.
> Inner Focus prevents the Pokémon from flinching. Pokémon with this
> Ability can still flinch due to a Pokémon with Mold Breaker, Teravolt
> or Turboblaze.