Here is the question that came up in our current game.

Thorg taunts a Holy Avenger that is already in Thorg's zone. The Warlord also has a Dwarf on Guard in the zone.

The priest uses a Guardian Angel to melee attack Thorg which removes his Guard marker.

Question #1-
Since the Holy Avenger can no longer perform the Mandatory Action of Thorg's taunt due to him no longer being an eligible target, can the Holy Avenger now take whatever legal actions he wishes including leaving the current zone?

Question #2-
If the same situation existed, but the Holy Avenger was in an adjacent zone when he started his Action Phase with Thorg's Taunt on him, must he fulfill a portion of the Mandatory Action even though he cannot complete all of its requirements? So, in this situation would the Holy Avenger
(1) need to move into Thorg's zone before it was relieved of the Mandatory Action or
(2) since he can see that the guard prevents him from attacking the creature taunting him, he is free to take any legal action including moving to a different zone?