Without another word, Galen reached into his robes and pulled out his wand as fast as his body could move- which was pretty damn fast. He flicked it at Melvin and said, "Stupefy!"
It was the same tactic Vader always used; catch them off guard, give them no time to react. It tested their natural reflexes. Of course since Galen could never use magic to defend himself, he'd always had to find other ways to defend against the attacks. Melvin had it easy.