Gomer has the opportunity to band before you play Freedom.
So the order goes:
You attack with a Red Hero.
Opponent blocks with Gomer.
Opponent chooses if he wants to use Gomer's ability and band in another Evil Character.
Assuming you are now losing the battle, you can play Freedom to remove Gomer.
If your opponent chose not to band, then it is now too late to use Gomer's ability.
