Unfortunately, I'm pretty sure that this card does nothing in most situations. By interrupting the battle, you are actually putting everything in a state where the SA causing you to be removed from battle is not happening. Thus, you could not withdraw.
Once you use interrupt, the SA just isn't there anymore, so you'd have to word it more simply like "If used by a Warrior-Class hero, Interrupt the Battle and return hero to your hand or discard..." (not sure what else was to be there, it got cut off I guess). I think you could have it start a conditional "If your Warrior-Class hero is being removed from battle, you may Interrupt..." but I'm not sure.