Is it wrong that as soon as John swallowed the key, I would've killed him, cut out the key, unlocked Gwen, and dumped his corpse in the rift?

I was hoping Jack would hack off his hand and shove him into the rift and free Gwen later with some savvy trick. That would have been cool. And boy, if so, wouldn't it be angsty to find out about this Grey person at the last moment.