Indeed. The "makes things run away" is an INTENDED feature of the power. It is a defensive ability, not an offensive one. You're overwhelmed, too many enemies beating on you? Hit Burn, gives you breathing room. THAT was the original intention. I'm not saying that's how we generally use the power these days, or ever, but the Cryptic devs thought that was how Burn was supposed to be used. And yes, immobilized? Burn your way out.