Hikaru could still come up with the technique, rewound or not... she came up with it once, she could come up with it again. I mean, you shoot her with an AM dart, and she'll definitely use spirit energy, around magic or not. Final defense. AND if she did use her spirit and die, she wouldn't die, she'd become ingrounded. Such is the subgrounded state. You lose.
Try this...
It's the obvious. Who can defeat the Sage Three? The Sage Three! What have they always had trouble with? Fighting amongst themselves. Cause them to have arguments and fight themselves and have them kill each other. Of course.. they'd still become Ingrounded. But eh.