Your also not likely to win without a super in that situation anyhow. If you melee a Bladedancer and get Flame Shield you stand a good chance of winning the fight. And that's if they decide not to Razors Edge you. Challenged a Defender in His bubble has never been a good idea. Barrier melee only stays active for a short time you also need a melee kill for it to activate not just a hit. So that means you already got into a fight and have low actual health. If you come upon a Bladedancer within the amount of time that Force Barrier is still up you probably don't have full health and are likely to die.