Meh, I'm always slightly displeased with issue where guest characters get taken down with such contemptuous ease they do it off panel. Case in point Cosmic Boy and Saturn Girl... both taken out without seeming to have made any sort of impact on Silver Sword, or alert the others. Is he THAT immune to telepathy and someone who can manipulate any magnetic metal?
Good rule of thumb; when you actually have someone (in this case Ferro) ask "How did they get taken out so quickly?" and it's a valid question, answer them!