Bard's Enthrall and running away

[Raikou]

So this has been bugging me when my friends and I played.

I was a bard and successfully enthralled them. They told me they could just simply choose to run away by rolling a dice(5,6) and thus not giving me aid.

I thought once enthralled they were forced to help me and can only run away if the main battler(myself) chooses to run away. Or they have a specific card that lets them avoid combat.

Thanks