It's not that Bob's a coward, it's just that he's practical. He knows when an opponent is too powerful for him, and he sees no shame in leaving. He'd rather walk away than lose, that's all. Besides, this way, he can come back later and make Mynd really suffer.
Come to think of it, I have no idea why Bob didn't bother trying to attack himself. I mean, he never tried using his fire powers on Mynd during their first confrontation, so why not try them now? If I had to guess, I'd say it was either because Bob was still smarting from that last encounter, or he saw no reason to get involved in this conflict. I mean, he's supposed to be evil, right, so why risk his life to save the good guys?
By the way, aren't all heroes required have to have an ultimate attack that they don't use until the very last minute when things are most desperate?
Megami was an artist that did artwork for the site. You can find her work, which includes over 500 pieces, on the downloads page. It was around this time that she had just created her own evil alter-ego, called Maverick Megami. It seemed appropriate that Helmut would be attracted to her.